●The crank bolts are made of steel material, strong and durable. With plastic seal on the outside (no separate crank lid required) ●Fit for crank systems with ISIS bottom bracket with M8 thread ●Our 8mm hex mounting screws are easy installation, a good replacement for repairing cranksets, suitable for any square hole crankset and bottom bracket. ●Bicycle crank screw with screw cap (screw adhesive), protects against vibration loosening as well as unwanted screw loosening and provides protection against corrosion. ●You will receive 4 pieces bicycle M8 crank bolt.