Without a doubt, Bitcoin hardware wallets are the most secure type of Bitcoin wallet. What differentiates hardware wallets from software wallets is that when they are plugged outin cold storage.
Trezor and Ledger wallet is one of the most well known bitcoin hardware wallets on the market. The device features an OLED display also stores Altcoins.
Digital Bitbox is one of the smallest Bitcoin hardware wallets on the market. It can be stored and concealed virtually anywhere.
Only downside to this is that its easier to misplace than an average hardware wallet.
The Ledger Nano S is a hardware wallet that can be used to store bitcoin and Altcoins.
It is one of the most popular cold storage wallets on the market, the Nano S connects to a computer via USB and features an OLED display that makes it easy to check and confirm transactions by pushing the buttons on the side of the device. Security is beefed up with the aid of Universal Second Factor authentication.