Material: Made of good quality aluminum alloy material, anti rust, high strength, sturdy and durable, colorfast, lightweight .
Functional: used fix the crank and crank of the sprocket .
Washer: Use double washer, Compatible with 21-23mm inner diameter cranksets .
Wonderful Accessory: for bike chain wheel, used fix the crankset and crank of the chain wheel, Tighten, seal, and waterproof.
install: crank arm Bolt is wonderful replacement part for your broken or old ones .
Universal: Can be applied for mountain bikes, road bikes, etc .