Features 1、Excellent Workmanship: Bicycle chain guide is made aluminum alloy and nylon material, T6 heat treatment, CNC turning, anodizing, lightweight design, fine workmanship. 2、Chain Guide Functions: This mountain bicycle chain guide is used in pipes in frame to effectively prevent the chain from falling off and moving. 3、Smoother 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. 4、Installation Process: For the bottom bracket chain guide, the bottom bracket and crank must be removed before installation, and then installed on the bottom bracket. 5、Applicable Specifications: Chain guide fits for threaded bottom bracket (press in type is not currently supported), bottom bracket chain guide is compatible with 30‑40T round tooth. Item Type: Bicycle Chain Gide Material: Aluminum Alloy + Nylon Weight: Approx. 61g/2.2oz Application: for Threaded Bottom Bracket (Press In Type Is Not Currently Supported) Package List 1 x Bicycle Chain Guide 2 x Gasket 2 x Hex Wrench