A hardware wallet is a physical device that is used to store cryptocurrencies, such as Bitcoin and Ethereum. It is a type of cold storage, which means that it is not connected to the internet and is therefore considered to be more secure than online wallets. A hardware wallet stores the private keys for a cryptocurrency offline, in a secure environment that is protected by a PIN code and other security measures. This makes it difficult for hackers to steal the keys and access the funds. Hardware wallets are portable and easy to use, and they are considered to be one of the most secure ways to store cryptocurrencies. Some popular hardware wallets include the Ledger Nano and the Trezor.