This is an old Fender factory mod – circa mid 80’s.
Original Fender TBX tone control suitable for most Strats and Teles - as used on the Eric Clapton Strat. Part# 099-2052-000
Comes in original Fender® packaging and includes 250K audio pot, 1M linear ganged pot, .022UF capacitor, 82K ohm resisitor and White Tone knob.
Some instruments have a unique tone circuit that features a TBX Tone Control (Patented). The TBX (which stands for Treble Bass Expander), is a dual concentric stacked tone pot. The pot has a detent in the middle position. From 0 to 5 (at the detent), the TBX functions like a normal tone circuit with filtration through a capacitor.
Advancing the knob counterclockwise from the detent position gradually filters off high frequencies, like a standard tone control.
Rotate the knob clockwise from the detent position, and you add presence and brightness by allowing the pickups' natural resonance to come through.
Measures:
24mm diameter body.
<3/8" Shaft length (9.5mm)
3/8" Thread length
3/8" Thread diameter (3/8-32 thread)
40mm overall length