This is an Alpha W Taper pot, as used in the Tube Screamer and other circuits like the GuitarPCB SuperSonic-02. The W Taper has an audio (logarithmic) curve to the halfway point, and then switches to a reverse-log (or anti-log) taper from the middle to the end. So the adjustment is aggressive for the first third, flatter for the middle third, and then more aggressive toward the end of the rotation.
Alpha part number is RV16AF-10-15R1-W20K. These are the same Alpha pots you might get from other sources. During the COVID-19 pandemic, the solder lug version of this was so difficult us to find, when we did find some for sale in bulk, we decided to stock them for sale in our store.
RV16AF-10 is the Alpha model number for a 16mm diameter solder-lug potentiometer. 15R1 in the model number means a 15mm shaft length (including threads) and 6.35mm (1/4 inch) diameter shaft. The threads are 6.5 mm long, and the section of the shaft extending beyond the threads is 8.5 mm.
Select 1 piece or the economical 5-pack.