Original TBX tone control for most Strats and Teles. CTS manufactured, includes capacitor and comes in original Fender® packaging. 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.