These are Hipshot tuners that came with an Xotic XPJ1T Precision Bass. Apparently, Xotic has them custom-made, and the mounting hole diameter is smaller than the standard Hipshot 1/2 size. Measurements are as follows: Tuner post diameter: 13mm Mounting hole diameter: 16mm These were included with an instrument I purchased new a few months ago. Since it's a relic model, there are some minor scratches on the tuner buttons, etc.