Purchase includes one replacement Pitlock seat pressure washer. The compression washer is installed between the seat collar and the lock mechanism housing, and is a critical piece of the Pitlock closure. The fluting assures that the lock has the grip required to function.
Please note that this product is not intended for use with wheel skewers. Pitlock wheel skewers require a different pressure washer, which can be found here.
Compression washers are made of high quality, stainless steel.