ALUMINUM bicycle axle washers for 3/8" axles "PC" logo laser engraved on one side (can be installed with either side facing out). Inner diameter: Fits 3/8" axles Outer diameter: 25.4mm (1") Thickness: 2.5mm (1/10") Material: 6061 Aluminum alloy Weight: 11g total weight for the entire set of 4 SOLD IN SETS OF 4