Features1Aluminum Alloy Material: The bike crank arm set is made of aluminum alloy material, which has light weight, high strength and fashionable appearance. 2Multi Stripe Fixing: The bike crankset is precisely processed and adopts multi stripe fixing method to ensure the ultimate retention of the chain, extend the working life, and reduce friction and noise. 3Bottom Bracket: BC1.37in X24T hollow integral tooth disc bottom bracket is suitable for most 68mm or 73mm long frame five way joints, suitable for 24mm crank of axle center, with a weight of about 104g. 4Crank Size: The BCD of the crank is 104mm/4.09in, and the length of the crank arm is 170mm/6.69in. This set is suitable for most mountain bikes and road bikes on the market. 5Well Equipped: This set includes 2 cranks, a bottom bracket, 36T positive negative tooth disc, 3638T protective disc, dust covers, screws and nuts.SpecificationItem Type: Bike hollow crank setMaterial: Aluminium alloyWeight: Approx. 1028g/36.3ozCrank: 170mm/6.7inCompatible: 8 9 10 11 speedSpecification: BCD 104mm/4.1inPackage List2 xHollowCrank1 xBottom Bracket10 x Screw8 x Nut2 x Dust Cover1 x Positive Negative Tooth Disc1 x Protective Disc