TREZOR is an isolated environment for offline transaction signing and using a small display you can visually verify the transaction contents. That's why all operations using TREZOR are entirely safe.
The ultimate in ease of use and super high levels of security. A Bitcoin safe if you like. Trezor keeps private keys on its device and signs transactions through hooking up via USB. So you will need a wallet such as Mycelium on your phone or desktop. Trezor lowers the risk of your private keys being discovered even if your PC is compromised by malware.
Screenshots from website
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