Park Tool SBC-1 Spoke ruler Cotter and Ball Bearing Gauge. This handy shop aid is ideal for sizing spokes ball bearings and crank cotters.

Has both metric and fractional spoke length markings

For Spokes: Hang the head of the spoke in the oblong hole and read its length on the scale

For Crank Cotters and Ball Bearings: Works just like a gauge for drill bits

Anodized aluminum with embossed markings to allow easy reading and long life