The Boss TW-1 T Wah is a vintage, analog envelope filter pedal produced by the Roland Corporation from 1978 to 1989. It was Boss's first compact envelope filter pedal, automatically sweeping a low-pass filter in response to your picking dynamics rather than requiring a traditional manual treadle foot-pedal.

Controls & Functions
The streamlined interface features two knobs and one toggle switch to shape your sound:

• Sens (Sensitivity): Adjusts how responsive the filter is to your picking strength. Turning it clockwise opens the filter with a lighter touch, while turning it counterclockwise accommodates heavy, aggressive picking styles.
• Peak: Modifies the overall depth and frequency coloration. Turning it clockwise creates a deep, resonant effect, while counterclockwise results in a shallower tone.
• Drive Switch (Up/Down): Controls the direction of the automatic filter sweep. In the UP position, the sound shifts from high range to low range (hard to mellow). In the DOWN position, it reverses, sweeping from low range to high range (mellow to hard)
• Condition: While the exterior has seen many concerts and shows plenty of wear the interior look like new and it has been tested and it functions perfectly