Tool needs either a 5/8 or 16mm spanner or just an adjustable spanner. This tool is incredibly simple to use and requires no rocket science. Remove the bolt in the crank arm Screw in and continue to tighten the silver piece of the tool until the crank starts to move. Screw the lower black part of the tool into the crank till tight. Tool needs either a 5/8 or 16mm spanner or just an adjustable spanner. This tool is incredibly simple to use and requires no rocket science. Remove the bolt in the crank arm Screw the lower black part of the tool into the crank till tight (ish) Screw in and continue to tighten the silver piece of the tool until the crank starts to move Package included: -1 ¡ BIKE CRANK EXTRACTOR REMOVER PULLER TOOL