Features1[Aluminum Alloy Crank] The crank is forged from high strength aluminum alloy, with widened and thickened edges and corners, which are easy to be stressed without breaking. 2[Shaft Chromium Molybdenum Steel] Shaft chromium molybdenum steel, the stability of crank and hollow shaft is improved. 3[External Thread Bearing] External thread bearing center shaft, aluminum alloy outer frame improves rigidity, reduces noise, and is easy to maintain and lubricate. 4[Stable and No Loosening] Exquisite thread, threaded pair lock, strengthen the stability of the lateral direction, will not loosen, and then there will be no abnormal noise. 5[Applicability] Suitable for modification of mountain bikes, road bikes, and folding bikes, suitable for crank sprocket 130mm, applicable range of bottom bracket 68-73mm for bottom bracket, bottom bracket thread specification BC1.37-24T.SpecificationItem Type: Hollow Integrated CrankMaterial: Main Aluminum Alloy, Shaft Chromium Molybdenum Steel, Bottom Bracket Tube PPCrank Size: Aperture Approx. 170mm / 6.7inCrank Shaft Size: Length Approx. 116mm / 4.6in, Outer Diameter Approx. 24mm / 0.9inCrank Shaft Inner Diameter Thread Specification: M18 ThreadApplicable Crank Crankset BCD: Approx. 130mm / 5.1inBottom Bracket Size: Total Length Approx. 91.5mm / 3.6in, Inner Diameter Approx. 24mm / 0.9in, Outer Diameter Approx. 44.6mm / 1.7inBottom Bracket Thread Specification: BC1.37in-24TOuter Diameter of Bottom Bracket Thread: Approx. 34mmBottom Bracket Type: ThreadedScope of Application of the Bottom Bracket: Approx. 68-73mm Bottom Bracket, and the Inbuilt Sealed Bearing Rotates SmoothlyPackage List1 x Right Foot Side Crank (with Shaft)1 x Left Foot Side Crank2 x Crank Hole Cover2 x Crank Fixing Screws5 x Short Screws5 x Nut2 x BearingBottom Bracket Lock1 x Bottom Bracket Sleeve3 x Bottom Bracket Washer