It's Pa. Game Commission issued number that allows you to use this number instead of your name and address on your name tags. When using the trapper's ID number only Game Commission personal can access your name and address. If an average citizen comes across one of your sets the only identifying mark they will see the the number on the trap tag. The number is good for life. You only need notify the Game Commission of your new address if you move. You can get the proper form to get an ID number by calling your regional office of the Game Commission.