Features1 Workmanship: Bicycle chain guide is made aluminum alloy and nylon material, T6 heat treatment, CNC turning, anodizing, lightweight design, fine workmanship. 2Chain Guide Functions: This mountain bicycle chain guide is used in pipes in frame to effectively prevent the chain from falling off and moving. 3Smoother Riding: Bike chain guide is used for single piece flywheel, and it runs more smoothly. The bottom bracket and crank need to be removed before installation. 4Installation Process: For the bottom bracket chain guide, the bottom bracket and crank must be removed before installation, and then installed on the bottom bracket. 5Applicable Specifications: Chain guide fits for threaded bottom bracket (press in type is not currently supported), bottom bracket chain guide is compatible with 3040T round tooth.SpecificationItem Type: Bicycle Chain GideMaterial: Aluminum Alloy + NylonWeight: Approx. 61g/2.2ozApplication: for Threaded Bottom Bracket (Press In Type Is Not Currently Supported)Package List1 xBicycleChainGuide2 x Gasket2 x Hex Wrench