Alpha CTS-style 250K linear potentiometer, brass thread
Thread:
US diameter 9.5 mm (3/8")
Length 11 mm
Solid shaft 6 mm (not 6.35 mm like US pots)
Very good quality, made in Korea by Alpha
Audio or linear: which one should you choose?
An audio (logarithmic) potentiometer follows the way your ear perceives volume: the rise is gradual over the entire rotation of the knob. It is the original choice on electric guitars for volume, and the most common one for tone.
A linear potentiometer changes at a steady rate. On volume, the sound barely drops over most of the rotation, then falls off suddenly at the very end. On tone, some guitarists like it for its more spread-out action.