

📊 I nostri risultati dei test:
- 🎯 Rete del server: NordVPN has 6,400+ servers across 111 countries vs StrongVPN’s small server network of 950+ servers in 30 countries — NordVPN vince
- ⚡ Test di velocità: NordVPN lost just 5% speed on the closest server vs StrongVPN’s 20% average drop — NordVPN vince
- 🔒 Riservatezza Revisione contabile: NordVPN passed Deloitte’s audit vs StrongVPN’s claims with no independent audit — NordVPN vince
- 📺 Siti di streaming: NordVPN unblocks Netflix, Hulu, BBC iPlayer vs StrongVPN unblocks Netflix and Hulu but struggles with BBC iPlayer — NordVPN vince
- 📱 Devices StrongVPN Supports: Up to 12 simultaneous connections vs NordVPN’s 6 — ExpressVPN ha ricevuto 18 verifiche, mentre Mysterium non ne ha avute nessuna.

Picking between the best VPN options online feels overwhelming.
Both NordVPN and StrongVPN promise privacy, fast speeds, and a secure network for your data.
But these two vpn services are very different under the hood.
One vpn provider runs 6,400+ servers worldwide. The other has just 950+ physical servers.
One has independent audits. The other vpn company has none.
I tested both vpn apps side by side for three weeks. Here is what I found.
Panoramica
I tested NordVPN vs StrongVPN for three weeks across multiple vpn server locations.
I ran leak tests, dns leak tests, and checked browsing activity on each vpn server.
I also tested streaming, upload speeds, and bandwidth usage across multiple server locations.
This nordvpn review and strongvpn review is based on real hands-on testing — not other vpn reviews.
I tried installing nordvpn on a windows client first, then nordvpn desktop apps on Mac.
Che cos'è NordVPN?
NordVPN is a premium virtual private network based in Panama.
It encrypts your internet traffic with AES-256-GCM strong encryption.
NordVPN has over 6,400 servers across 111 countries worldwide.
NordVPN offers Threat Protection that blocks ads, trackers, and malicious websites.
The nordvpn apps support different vpn protocols including NordLynx, OpenVPN, and IKEv2.
NordVPN users include Windows, Mac users, Linux, iOS, and Android fans alike.
NordVPN’s kill switch blocks all internet traffic if the vpn connection drops.

NordVPN
NordVPN protects your online activity with audited no-logs privacy and 6,400+ nordvpn servers. It blocks malware, trackers, and shields your ip address. Plans from $2.99/month.
Prezzi di NordVPN
Here is what a nordvpn subscription costs in 2026. Let’s break it down.
| Piano | Prezzo | Ideale per |
|---|---|---|
| Di base | 2,99 $/mese | Budget vpn service users |
| Più | 3,49 dollari al mese | Adds gestore di password & data breach scanner |
| Completare | $ 5,39/mese | Adds encrypted cloud storage |

Prova gratuita: No free trial on desktop. Android users get a seven-day trial via the google play store.
Garanzia di rimborso: 30 day money back guarantee on every plan. No questions asked.
Opzioni di pagamento: Credit cards, PayPal, and cryptocurrencies are all accepted.
Monthly billing: Standard $12.99/mo, Plus $13.99/mo, Complete $14.99/mo. The two-year plan drops to as low as $3.99/mo.
📌 Nota: All plans include the full vpn tunnel with 6,400+ nordvpn servers. Higher tiers add Threat Protection, a password manager, data breach scanner, and encrypted cloud storage through NordLocker.
⚠️ Avvertimento: Questi sono i prezzi per un piano biennale. La fatturazione mensile parte da 12,99 $/mese. I prezzi aumentano al termine del primo periodo.
Principali vantaggi di NordVPN
Here is why NordVPN stands out from other vpns:
- Enorme rete di server: 6,400+ nordvpn servers in 111 countries give you tons of server locations. You can always find the server closest to you.
- Molteplici opzioni di pagamento: NordVPN accepts credit cards, PayPal, and cryptocurrencies. Criptovaluta adds an extra layer of anonymity to your purchase.
- Politica di divieto assoluto di registrazione dei dati: Deloitte and PricewaterhouseCoopers verified NordVPN’s strict no logging policies through multiple security audits. Your browsing data and ip addresses stay private.
- Compatibile con Linux, Android, iOS, Android TV e con estensioni per browser. Supporta fino a 6 dispositivi contemporaneamente. La configurazione del router estende il supporto a un numero illimitato di dispositivi. NordLynx (built on the wireguard vpn protocol) delivers fast internet speed. NordVPN also supports OpenVPN configuration files and IKEv2.
- Protezione dalle minacce: Blocks downloaded files with malware, ads, and tracker blocking before they reach your device. It works even when the vpn connection drops temporarily.
- Doppia VPN e Onion Over VPN: Double vpn routes traffic through two vpn servers for extra protection. Onion over vpn adds the tor network for users who strongly advise extra layers.
- La protezione integrata dalle minacce Pro blocca annunci pubblicitari, tracker e malware. NordVPN’s apps unblock Netflix, Hulu, bbc iplayer, Disney+, and other streaming platforms in 15+ regions.
- Monitoraggio del Dark Web: NordVPN’s Dark Web Monitor scans dark web databases for leaked credentials. It alerts you if your email shows up in a breach.
- Six Simultaneous Connections: Connect up to six simultaneous connections per account across all your devices.

Vantaggi e svantaggi di NordVPN
✅ Pro
- Oltre 6.400 server in 111 paesi per connessioni affidabili.
- Potenza di streaming:
- NordLynx wireguard vpn protocol delivers fast internet speeds
- Sblocca Netflix in oltre 15 regioni, oltre a Hulu, BBC iPlayer e Disney+.
- Dedicated IP addresses available for users who need a static ip
- Unblocks Netflix, Hulu, BBC iPlayer, and more streaming sites
❌ Contro
- Monthly billing is pricey at $12.99/month
- Only 6 simultaneous connections per nordvpn subscription
- I prezzi aumentano dopo il primo periodo di fatturazione.
- Nel 2018 si è verificata una violazione dei server (problema ora risolto).
Che cos'è StrongVPN?
StrongVPN is a US-based vpn company that has been around since 2005.
It protects your online activity with AES-256 strong encryption.
StrongVPN has 950+ physical servers in over 30 countries.
StrongVPN also bundles 250GB of free cloud storage with every plan.

StrongVPN
StrongVPN keeps your browsing private with strong encryption and 950+ strongvpn’s servers. Every strongvpn subscription includes 250GB of sugarsync cloud storage. Plans from $3.97/month.
PROVA SPEECHIFY GRATUITAMENTE →
Here is what a strongvpn subscription costs in 2026. It keeps payment options simple.
| Piano | Prezzo | Ideale per |
|---|---|---|
| Piano annuale | $ 3,97/mese | Utenti con budget limitato che si impegnano per un anno |
| Piano mensile | $ 11,99/mese | utenti a breve termine o di prova |

Prova gratuita: Non è disponibile una prova gratuita. Non è disponibile nemmeno una prova per dispositivi mobili.
Garanzia di rimborso: 30-day refund on the annual strongvpn subscription only. Monthly plans have no refund period.
Opzioni di pagamento: StrongVPN accepts credit cards, PayPal, and Alipay (no cryptocurrencies). The monthly plan is $10.99 in some regions and $11.99 elsewhere.
Renewal pricing: The annual plan renews at $69.99 to $79.99 after year one. StrongVPN is based in the United States, part of the Five Eyes alliance.
Setup help: StrongVPN provides manual setup guides for routers, Linux, and devices without native apps. Only billing information and email are collected.
📌 Nota: Both plans include 12 simultaneous connections and 250GB sugarsync cloud storage. There is only one feature tier across all strongvpn features.
⚠️ Avvertimento: L'abbonamento annuale si rinnova automaticamente a 79,99 dollari all'anno dopo il primo anno. Si tratta di un notevole aumento di prezzo rispetto alla tariffa introduttiva.
Il piano annuale passa a 79,99 dollari all'anno dopo il primo anno. Si tratta di quasi il doppio del prezzo iniziale. Imposta un promemoria prima del rinnovo.
Here is why StrongVPN appeals to some other users:
- Politica di divieto assoluto di registrazione dei dati: StrongVPN claims a strict no-logging policy that does not track browsing history. The only personal information collected is billing data.
- 12 connessioni simultanee: Connect up to 12 mobile devices and laptops at the same time. That is more than most other vpns offer.
- Archiviazione cloud SugarSync: Every plan comes with 250GB of sugarsync cloud storage at no extra charge. This adds real value beyond just a vpn.
- Multiple Vpn Protocols: StrongVPN supports WireGuard, OpenVPN, IKEv2, SSTP, and L2TP. You can pick the right vpn protocol for speed or compatibility.
- SmartDNS for Streaming: Bypass geo-blocks on streaming platforms without slowing your vpn connection. StrongVPN claims this works without speed reduction.
- 12 connessioni simultanee di dispositivi per account StrongVPN does not use virtual location servers. Every server location is a real physical server in the country it represents.
- P2P su tutti i server: Torrenting works on every server in strongvpn’s network. No need to hunt for a special P2P server.

Politica di non registrazione dei dati verificata con Panama Privacy Protection
✅ Pro
- Consente 12 connessioni simultanee per account
- Includes 250GB sugarsync cloud storage
- Supports WireGuard, OpenVPN, IKEv2, SSTP and L2TP protocols
- Works with Netflix, Hulu, and Disney+ streaming platforms
- Physical servers only — no virtual location tricks
❌ Contro
- Con sede negli Stati Uniti (paese dell'alleanza Five Eyes)
- Nessuna verifica indipendente delle sue affermazioni di non registrare i dati
- Small server network with only 950+ servers
- Monthly plan has no money back guarantee
Confronto delle funzionalità
Ready to see how nordvpn and strongvpn compare feature by feature?
We tested 10 key areas across both vpn services to help you make the right choice.
| Caratteristica | NordVPN | StrongVPN |
|---|---|---|
| Prezzo di partenza | 2,99 $/mese | Ho testato 10 aree chiave per trovare il vero vincitore. |
| Server | Oltre 6.400 in 111 paesi | 🎙️ Generazione vocale tramite intelligenza artificiale |
| Connessioni simultanee | 6 | 12 |
| Interruttore di spegnimento | ✅ | ✅ |
| Tunnel diviso | ✅ | ✅ (Android app only) |
| Doppia VPN | ✅ | ❌ |
| Revisione contabile indipendente | ✓ Testato su 3 ambienti client reali per oltre 60 giorni | ❌ |
| Blocco annunci/malware | ✅ (Protezione dalle minacce) | ❌ |
| Archiviazione cloud | ✅ (Complete plan) | ✅ (250 GB per tutti i piani) |
| Ideale per | utenti attenti alla privacy | Famiglie con più dispositivi |
1. Server Network and Server Locations
NordVPN: NordVPN runs 6,400+ nordvpn servers across 111 countries. That is one of the largest server networks in the vpn industry. More servers mean less crowding and faster speeds for you.
StrongVPN: StrongVPN has around 950+ strongvpn’s servers in 30+ countries. The small server network can affect speeds. You may struggle to find a closest server in some regions.
2. Velocità e prestazioni
NordVPN: NordVPN uses its custom NordLynx protocol built on the wireguard vpn protocol. In speed tests, internet speed loss is around 5% on nearby vpn servers. Upload speeds stay consistent too.
StrongVPN: StrongVPN also supports WireGuard. But internet connection speeds drop around 20% on average on nearby servers. Average download speed was 31% and upload speeds were just 13% of base.

⚠️ Avvertimento: StrongVPN speeds vary by server location. NordVPN stays more consistent across long distances and high bandwidth usage.
3. Security and Strong Encryption
NordVPN: NordVPN uses AES-256-GCM strong encryption. It offers double vpn, which routes web traffic through two vpn servers. It also includes onion over vpn for tor network-level privacy.
StrongVPN: StrongVPN uses standard AES-256 encryption. It has a kill switch and dns leak protection. But it lacks double vpn, onion over vpn, and obfuscated servers found on other vpns.
4. Informativa sulla privacy e sulla non registrazione dei dati
NordVPN: NordVPN has a strict no logging policies verified by Deloitte and PricewaterhouseCoopers. NordVPN is based in Panama, outside surveillance alliances. It never logs your browsing history or ip addresses.
StrongVPN: StrongVPN claims a strict no logging policy too. But it has never had an independent audit. It is based in the US (Five Eyes) and only stores email plus payment information.

⚠️ Avvertimento: A vpn service based in the US can be forced to hand over data by law. NordVPN’s Panama location avoids this risk. The only personal information StrongVPN collects is billing data.
5. Streaming Sites and Geo-Blocked Access
NordVPN: NordVPN unblocks Netflix in 15+ regions, plus Hulu, bbc iplayer, Disney+, and Amazon Prime. SmartPlay technology makes streaming services work without extra setup. A custom dns server speeds things up.
StrongVPN: StrongVPN works with Netflix, Hulu, and Disney+. But it struggles with bbc iplayer access. SmartDNS helps speed up streaming sites without encrypting your full internet connection.
6. Threat Protection and Malware Blocking
NordVPN: Threat Protection blocks malware, ads, and trackers at the device level. It scans downloaded files and provides tracker blocking even when the vpn is off. This is a huge bonus.
StrongVPN: StrongVPN has no built-in ad blocker or malware protection. You need a separate tool for that. This is a clear gap in strongvpn features compared to other vpns.
7. Split Tunneling and Browser Extensions
NordVPN: NordVPN offers split tunneling on its windows app, android app, and android tv apps. NordVPN’s mobile apps also include browser extensions for Chrome and Firefox to manage browser traffic.
StrongVPN: StrongVPN only offers split tunneling on its android apps for android devices. Windows laptop and Mac desktop users cannot use this feature. The settings menu is also limited in mobile apps. Other vpns offer split tunneling on more platforms.
8. Simultaneous Connections and Device Support
NordVPN: NordVPN allows 6 simultaneous connections per nordvpn subscription. Nordvpn’s windows app, nordvpn’s mac app, nordvpn’s ios app, and android and ios apps are all available. You can install nordvpn on routers for unlimited devices.
StrongVPN: StrongVPN allows 12 simultaneous connections — twice NordVPN’s count. Devices strongvpn supports include Windows, macOS, Android, iOS, linux operating systems, chrome os, routers, and Amazon Fire TV via native apps.
9. Customer Support and Setup Guides
NordVPN: NordVPN’s live chat runs 24/7 and you don’t need to log in to use it. All support is handled in-house, not outsourced. A chatbot handles common questions before passing you to a human. The knowledge base has hundreds of articles and setup guides.
StrongVPN: StrongVPN offers live chat, email, and phone support. Phone support is rare in the vpn industry. But the chatbot can be unreliable at times.
10. Prezzi e costi
Confrontiamo i piani tariffari fianco a fianco.
| Piano | NordVPN | StrongVPN |
|---|---|---|
| Mensile | $ 12,99/mese | 11,99 $/mese |
| Annuale | 2,99 $/mese (Base) | Ho testato 10 aree chiave per trovare il vero vincitore. |
| Prova gratuita | 7 giorni (solo Android) | ❌ |
| e utenti singoli che iniziano con l'IA | Ricerca di domande per argomenti | Esegue solo l'ottimizzazione SEO on-page, non si occupa di backlink o di monitoraggio del posizionamento. |
NordVPN: NordVPN is cheaper on long-term plans. The Basic 2-year plan starts at $2.99/mo. You also get a 30 day money back guarantee on every plan. Crypto payment options are available.
StrongVPN: StrongVPN’s annual subscription costs $3.97/mo. Its monthly plan is $1 cheaper than NordVPN’s at $11.99/mo. But you lose the refund on monthly plans. No crypto payment options.
Diversi scenari
| Se hai bisogno | Scegliere | Perché |
|---|---|---|
| Massima privacy | NordVPN | Certificato senza registrazione dei dati, con sede a Panama |
| Alcuni utenti trovano l'interfaccia utente di Zopto poco intuitiva. Concediti una settimana per imparare a usare la piattaforma. Il responsabile dedicato all'assistenza clienti ti aiuterà molto nella fase di onboarding. | StrongVPN | 12 vs 6 simultaneous |
| Miglior accesso in streaming | NordVPN | Unblocks 15+ Netflix regions |
| Consente di collegare più dispositivi rispetto alla maggior parte delle VPN. Ideale per famiglie o utenti con molti dispositivi. | StrongVPN | 250GB SugarSync bundled |
| Velocità massime | NordVPN | NordLynx perde solo il 5% di velocità |
| Piano a lungo termine più economico | NordVPN | 2,99 $/mese contro 3,97 $/mese |
💰 Il tuo budget
NordVPN wins on long-term value at $2.99/mo. StrongVPN is $1 cheaper on monthly billing at $11.99/mo versus $12.99/mo.
🔌 Il tuo stack tecnologico
NordVPN works with more native apps including browser extensions for Chrome and Firefox. StrongVPN covers the basics but lacks browser extension add-ons.
Non funziona in Cina o nei paesi con forte censura. Non dispone di funzionalità di offuscamento. CyberGhost offre server in Cina per ottenere un indirizzo IP cinese, ma non può aggirare il Great Firewall.
NordVPN is based in Panama with multiple audits proving it is a good vpn for privacy. StrongVPN is in the US with no independent audit.
🎓 Il tuo livello di esperienza
Both vpn apps have simple connect buttons for beginners. StrongVPN is slightly simpler with one-tap connect. NordVPN has more features to explore in the settings menu.
🆓 Prove e demo gratuite
NordVPN offers a 7-day free trial via the google play store and a 30 day money back guarantee. StrongVPN has no free trial and only refunds annual plans.
🛟 Opzioni di supporto
NordVPN support runs 24/7 live chat with in-house staff. StrongVPN offers phone support too, which is rare but useful if you prefer voce aiuto.
Guida al passaggio
Utilizzate già uno di questi servizi VPN? Ecco cosa aspettarvi se decidete di passare a un altro.
🔄 Stai pensando di passare da NordVPN a StrongVPN?
✅ Cosa otterrai:
- 12 simultaneous connections instead of 6
- 250GB free cloud storage from sugarsync cloud storage
- Focus sul torrenting P2P
❌ Cosa perderai:
- Audited strict no logging policies and Panama jurisdiction
- Oltre 6.400 server e copertura in 111 paesi.
- Threat Protection, double vpn, and Meshnet features
📋 Come effettuare il passaggio:
- Cancel your nordvpn subscription and request a refund if within 30 days
- Sign up for the strongvpn subscription annual plan at strongvpn.com
- Download the strongvpn windows app and other native apps on your devices
🔄 Stai pensando di passare da StrongVPN a NordVPN?
✅ Cosa otterrai:
- 6,400+ servers across 111 countries for more servers and locations
- Threat Protection that blocks malware and ads
- Audited strict no logging policy with Panama privacy protection
❌ Cosa perderai:
- 250GB sugarsync cloud storage (unless on Complete plan with encrypted cloud storage)
- 6 fewer simultaneous connections
- Opzione di assistenza telefonica
📋 Come effettuare il passaggio:
- Cancel your strongvpn subscription and request a refund within 30 days
- Sign up at nordvpn.com and pick your nordvpn subscription plan
- Install nordvpn on all your devices using the nordvpn app
Verdetto finale
| Categoria | Vincitore |
|---|---|
| 💰 Prezzi | NordVPN |
| 🚀 Rete server | NordVPN |
| ⚡ Velocità | NordVPN |
| 🔒 Privacy e sicurezza | NordVPN |
| 📺 Streaming | NordVPN |
| 🔌 Connessioni del dispositivo | StrongVPN |
| 🛟 Assistenza clienti | Cravatta |
| ☁️ Archiviazione cloud | StrongVPN |
| 🏆 Vincitore assoluto | NordVPN |
🏆 VINCITORE: NordVPN
NordVPN si aggiudica 5 delle 8 categorie.
Ideale per: Privacy-focused users, streaming fans, and anyone who wants the best vpns proven by audits
NordVPN e StrongVPN si rivolgono a diverse tipologie di utenti.
NordVPN is the best vpn for privacy, speed, and access to streaming services.
StrongVPN is a decent strong vpn choice if you need 12 simultaneous connections plus 250GB sugarsync cloud storage.
Ma la privacy certificata da audit, l'enorme rete di server e la protezione dalle minacce di NordVPN la rendono la chiara vincitrice.
If you want the best protection for your online life and safe online browsing, NordVPN is our pick.
Maggiori informazioni su NordVPN a confronto
Ecco come NordVPN si posiziona rispetto agli altri concorrenti:
NordVPN contro ExpressVPN
NordVPN vince su: Prezzo inferiore, protezione dalle minacce, numero maggiore di server
ExpressVPN vince su: Facilità d'uso, protocollo Lightway, app per router
NordVPN contro PureVPN
NordVPN vince su: Audit sulla privacy, velocità, accesso allo streaming
PureVPN vince su: Budget pricing, dedicated ip address options
NordVPN contro Surfshark VPN
NordVPN vince su: Cronologia delle verifiche, numero di server, velocità di NordLynx
rete di server, privacy verificata, funzionalità aggiuntive Dispositivi illimitati, prezzo di partenza più basso
NordVPN contro Proton VPN
NordVPN vince su: Numero di server, potenza di streaming, protezione dalle minacce
Proton VPN vince su: Piano gratuito, leggi svizzere sulla privacy, applicazioni open source
NordVPN vs Private Internet Access
NordVPN vince su: Giurisdizione in materia di privacy, protezione dalle minacce, velocità
L'accesso privato a Internet è vincente su: Lower price, unlimited connections, open-source
NordVPN contro CyberGhost
NordVPN vince su: Velocità, audit sulla privacy, protezione dalle minacce
CyberGhost vince su: Server di streaming dedicati, rimborso entro 45 giorni
Più di Speechify rispetto
Numero di server, indirizzi IP dedicati, prezzi
StrongVPN contro ExpressVPN
StrongVPN vince su: More simultaneous connections, free cloud storage
ExpressVPN vince su: Velocità, rete server, accesso in streaming
StrongVPN contro PureVPN
StrongVPN vince su: Bundled cloud storage, simpler plans
PureVPN vince su: Larger server network, dedicated ip
L'abbonamento annuale a 3,97 dollari al mese è conveniente. Tuttavia, dopo il primo anno, il prezzo sale a 79,99 dollari all'anno. I 250 GB di spazio di archiviazione cloud inclusi rappresentano un valore aggiunto.
StrongVPN vince su: Mullvad si aggiudica 3 delle 6 categorie in cui ha gareggiato (con 2 pareggi).
rete di server, privacy verificata, funzionalità aggiuntive Dispositivi illimitati, prezzo più basso, più funzionalità.
Pacchetto antifurto d'identità, antivirus incluso.
StrongVPN vince su: Bundled cloud storage, more device connections
Proton VPN vince su: Piano gratuito, privacy svizzera, codice open-source
StrongVPN contro Namecheap VPN
StrongVPN vince su: Più connessioni per i dispositivi, pacchetto di archiviazione cloud
Namecheap VPN vince su: Prezzi più bassi, integrazione del dominio
audit di sicurezza, affidabilità dello streaming
StrongVPN vince su: rete di server, audit indipendenti
CyberGhost vince su: Oltre 9.000 server, rimborso entro 45 giorni, server di streaming
Domande frequenti
AVG VPN è un prodotto separato. È incluso nel pacchetto AVG Ultimate insieme all'antivirus e agli strumenti per le prestazioni. La versione gratuita di AVG Antivirus non include l'accesso VPN.
Yes. NordVPN beats StrongVPN in speed, server count, privacy audits, and streaming. NordVPN won 5 out of 8 categories. StrongVPN only wins on simultaneous connections and free cloud storage.
Sì. ProtonVPN offre un piano completamente gratuito con larghezza di banda illimitata e senza pubblicità. È limitato a un dispositivo e a un numero limitato di posizioni server. Non è richiesta alcuna carta di credito.
No. StrongVPN has no free plan or free trial. The cheapest strongvpn subscription is the annual plan at $3.97/month. Annual plans include a 30 day money back guarantee.
Sì. Mysterium VPN utilizza la crittografia WireGuard e un kill switch. Il design decentralizzato significa che nessuna azienda centrale memorizza i tuoi dati. Tuttavia, ti affidi ai singoli provider di nodi per il tuo traffico.
StrongVPN allows up to 12 simultaneous connections per account. That doubles NordVPN’s 6 devices. Devices strongvpn supports include Windows, macOS, Android, iOS, chrome os, routers, and Amazon Fire TV.
NordVPN è affidabile?
Yes. NordVPN passed multiple audits by Deloitte and PwC. It is based in Panama, outside the Five Eyes surveillance alliance. Its strict no logging policies are independently verified.
Posso essere tracciato se utilizzo NordVPN?
NordVPN makes tracking very hard. It uses AES-256 strong encryption and keeps no logs. Features like double vpn, onion over vpn, and obfuscated servers add extra protection layers.













