These are the best cryptocurrency
hardware wallets available.

Ledger Nano S

Ledger Nano S is a Bitcoin, Ethereum and Altcoins hardware wallet, based on robust safety features for storing cryptographic assets and securing digital payments.

It connects to any computer (USB) and embeds a secure OLED display to double-check and confirm each transaction with a single tap on its side buttons.

The Ledger Nano S is manufactured by Ledger.

 
Ledger Nano S - The secure hardware wallet

Trezor

The Trezor wallet comes in black or white and is in their words 'the original and most secure hardware wallet'.

Trezor supports Bitcoin, Ethereum, Litecoin and many other ALT coins/tokens, a comprehensive list of which can be found here.

Trezor Wallet is manufactured by SatoshiLabs.