1Premium Material: The bottom bracket shell is made of aluminum alloy, which is sturdy and durable. 2Superior Performance: The threaded system protects the frame and produces more power than the normal axle. 3Good Sealing: Double silica gel sealing ring is installed at the bottom port of the bracket to prevent pollution and prolong the service life. 4Better Effects: Compared with traditional bottom bracket, it has higher compatibility with chain ring and better waterproof performance. 5Applicable: ZTTO T47 Bottom Bracket outer diameter 47mm/1.9in, inner diameter shaft 30mm/1.2in, easy to install, perfect mountain bike accessories. Item Type: Bottom Bracket Material: Aluminum Alloy Outer Diameter: Approx. 47 mm/1.9in Inside Diameter: Approx. 30 mm/1.2in Bottom Bracket Shell: Approx. 86mm 2.7in, Approx. 73mm/2.9in 1 x Bottom Bracket