Thank you very much for viewing. This is an aftermarket product imported from overseas. This is a set of four "Guild Hat Knobs Silver". It's a set of 4 knobs: 2 for volume and 2 for tone. The size is approximately 28.0mm in outer diameter and 14.7mm in height. Compatible with metric pots. (Not compatible with inch-spec USA pots.) How about using these for repairing or replacing the knobs on your guitar?