Rubber washer for under pedal knobs, or strap lock
Boss Style Pointer Knobs | Time Travel Audio, Vintage Audio Equipment, Components & Servicing, Edinburgh, Scotland, UK
Pedal Builder's Vector Art Pack
WingMan Foot-Controlled Expression Knob & Danger Zone Tremolo/Phaser Effects Pedal
Amazon.com: DaierTek Guitar Effect Pedal Knob Metal Black Potentiometer Knob Anodized Aluminum Amp Pot Knob with Set Screw 1/4 -13Pack : Musical Instruments