Park tool spoke bearing and cotter gauge sbc 1this handy shop aid is ideal for sizing spokes ball bearings and crank cotters to use just hang the head of the spoke in the oblong hole and read its length on the scale for crank cotters and ball bearings it works just like a gauge for drill bits spoke lengths are in both metric and fractional markings made of anodized aluminum with embossed markings to allow easy reading and long life buypark tool workshop accessoriesfrom chain reaction cy