●The package includes 2 pieces of M18 crank arm mounting screws. Fits 18mm crank bolt ●The crank screw is made of aluminium alloy material, high strength, corrosion resistant, sturdy and durable. ●CNC machined with high precision for a burr-free finish and standard thread, fits perfectly to keep water, dust and other elements out. ●Easy installation with the UK 3/8" Allen key (10mm) (not included). ●The crank fixing screw is used to attach the crankset and crank of the sprocket and is suitable for mountain bikes and road bikes.