Wallet CW key
Empty wallet is a sad view. Don't throw it away though because you too can use it as a CW key.
First cut two pieces of aluminium sheet to the size of credit card. Connect a keying cable to them with tape.
Put the shining new "credit cards" into wallet pockets like this.
The cable and plug are stored in the coin pouch when they are not in use.
See & hear the video clip (it is free):