Nexx Racing's DISK DAMPER SET, Multi-length with plastic damper disk for smooth "droop" and 360 degree dampening. For the MR02, MR03 & PN2.5 chassis including; soft, medium, hard & extra hard REAR tuning springs that will allow for fine tuning of the chassis and adjustable "droop." Plastic disk come in 2 sizes; 12mm: for smooth contact surfaces & 15mm for smooth LOW friction surfaces.