The Ledger Nano S cryptocurrency hardware wallet provides a secure cold storage. You can safely keep several cryptocurrencies here. It is an electronic device. You can always carry it with you. Most of the assets supported by the Ledger Nano S hardware wallet are not supported by competing hardware wallets such as KeepKey or Trezor. This one step takes Led back forward. Despite the variety of supported cryptocurrencies, the disadvantage of Ledger Nano S; limited internal memory. It only allows you to install 3-5 different cryptocurrency wallets (depending on the size of the wallet apps). It is a great hardware wallet if you want to store several different crypto units or tokens (for example BTC and ETH). However, it is not an ideal solution for storing your entire altcoin portfolio.