10x Guitar Mini Effect Pedal Knobs 6mm Black w/ Silver Cap Knob for Boss Pedals | eBay
Amazon.com: DaierTek 10pcs Black Davies 1900h Clone Guitar Effect Pedal knob 1/4 Shaft Set Screw for Amplifier amp boss Volume Control : Musical Instruments
Guitar Pedal X - GPX Blog - Pedal Design 101 - All about Pedal Knobs, and why more brands should have their own signature versions