The coins in this series have several unique aspects. Instead of having a hologram sticker that is peeled off to access the private key, the holograms on these coins are ‘scratch off ’ surfaces. Upon being scratched (by perhaps, another coin), a QR code and written version of the private key is revealed. Due to the surface being prone to scratch when in contact with any hard object, these coins should be kept in a proper air-tight holder.
An interesting fact about the ‘1/2 BTC’ coin is that its value is marked as a fraction instead of a decimal like all other coins of that denomination.