A500K Audio 18mm Shaft (split) Mini Size Potentiometer

 A500K 18mm Split Brass Shaft Mini Potentiometer for volume and tone control on guitar.

D3 = Pot diameter: 16mm (mini size)

L = Shaft length: 18mm 

D1 = Shaft diameter: 6mm

D2 = Shaft diameter for knob: 6mm (split)

250k pots are usually used for volume control on any guitar and tone control on single coil pickups

500k pots are usually used for tone control on humbucker type pickups

Split shafts are suitable for push-on control knobs, solid shafts are suitable for knobs that have a tightening screw.

15mm Shaft pots are normally used for Fender style guitars or guitars with plastic pickguards that the pot goes through

18mm Shaft pots are normally used for Gibson style guitars as they often have wood that the pots must go through (or plastic pickguards if you purchase extra nut and washer to create a spacer at the back)

What is the difference between A pots and B pots?

"A" would denote an audio taper pot (most of the control happens between 7 - 10) and the "B" suffix would denote a linear taper pot (more even roll-off between 0 - 10)

A and B pots however are interchangeable and the only difference is the taper of the pot, or "how gradually it rolls off". Most manufacturers use either audio taper (A) pots for volume + tone or would use audio taper (A) for tone, and linear taper (B) for volume. This is also determined by player preference