A private key is 32 hexadecimal characters that give control over a bitcoin wallet address. These chips are supposed to contain private keys for addresses that each contain a little bit of bitcoin.
Personally, I have no confidence in schemes like this. You have to trust the people who created the wallet addresses, the people who funded the wallets, the printer who prints them, the manufacturer who puts it all together... And, if the "tamper evident" part is imperfect, you need to trust the reseller on eBay.
Also, the idea of a physical coin for a Bitcoin is inherently stupid to me.
DEVELOPERS: We've created new digital money that can be sent through the ether and cannot be physically taken from you!
PUBLIC: Great! Let's lock it to old-fashioned coins and lose all those benefits!
:
