I know DW has a regular spring and a heavy-duty spring. The heavy-duty spring provides substantially more resistance. I've been using them on my 5000 for almost fifteen years. Wouldn't go back to the regular spring...
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DW Heavy-Duty Drum Pedal Sp...
Pedal Mount PEIN (upgrade) is a device to keep your racing pedal and rudder pedal at a set distance from your chair as well as tilt the pedals to a more comfortable angle.