Quality CTS Vintage Taper Potentiometers - 250 & 500k-ohm.
500K-ohm pots are usually used with humbuckers and 250Ks are used with single-coil pickups.
You can use any value you like, but a 250K will give a slightly warmer tone than a 500K pot. The 250K pot bleeds off (attenuates) some of the high frequencies to ground.
CTS, 24 spline split knurled shaft with nut, lock and dress washer. Threaded bushing is 3/8" tall;