Bicycle cotter pin, model SC-FC-109, is a 45MM pin that locks the crank arm onto the bottom bracket axle. It has a 17/64” x 26 TPI thread and a diameter of 8 MM - 10.5 MM. The pin body carries a flat angled face along its length, and the threaded end is fitted with a hex nut and washer, all in a plain grey metallic finish.