A passive board that sits under the 6522 VIA in the Commodore 1541 disk drive allowing the device ID number to be changed without cutting the jumpers on the 1541 mainboard and instead routing the signals to two pairs of pin headers, which can then be used with jumpers or wired to DIP switches. The two sets of pin headers determine the device ID. They can then be opened or closed using pin header jumpers or wired to external DIP switches (may require cutting the 1541 case).

It is possible to use DIP switches without modifications to the 1541 case but it's not ideal. The fuse holder has some space between the case and holder which is just enough to sneak some 24AWG or thinner wires through. Obviously this is not the best way to do it, but it doesn't block access to any of the ports, and doesn't require any case cutting.