Used Between the Drive Side Crank Arm and Bearing for SRAM/Bontrager GXP Cranks, this wave washer is critical for drive side seal and bearing retention when running GXP crank sets in TREK BB90 and BB95 bottom brackets ("net molded sockets"). NOTE: Many of the RWC kits for Trek BB90/BB95 bottom brackets contain our own stainless steel "overlap wave spring." This is the Trek factory wave washer.