PDP PDDPCO Concept Series Double Pedal. Designed in California by Drum Workshop for optimal playability, the Concept Series Double Pedal is a boutique-inspired machine that’s quick and responsive. The pedalâs design is outfitted with a dual chain concentric drive system, smooth cast extended footboard with integrated needle bearing hinge, single post auxiliary pedal, telescoping linkage with universal joints, and an offset toe clamp. Post Frame with adjustable spring rocker. Solid base plate with Magnetic Drum Key.