A cold card is a type of hardware wallet, which is a device that stores cryptocurrency keys offline in a secure manner. Like other hardware wallets, a cold card provides an additional layer of security for your cryptocurrency holdings by keeping the keys that control access to your coins in a physically separate and secure device.

One key difference between the cold card and other hardware wallets is that it is designed to be an "air-gapped" device, which means it is physically isolated from the internet and other devices. This makes it more resistant to hacking attempts, as an attacker would need to physically access the device in order to compromise it.

As for your question about purchasing a cold card from Coinkite, it appears that the cold card package includes the device, a micro-USB cable, a power adapter, and a microSD card. You can find this information on the Coinkite website by clicking on the "In the Box" tab on the product page for the cold card.