Description: Use ultralight high - strength AL7075 Aluminium Alloy with high quality CNC machined . It can be used on the tube in the frame to effectively prevent the chain and chain from jumping . It needs to be small and light , and it must be strong and durable , so we use a solid aluminum alloy as material with high hardness and long service life . Novel hollow design , reduce weight , anti - chain effect is good , used for single - disc sprocket , make riding smoother and easier . The universal chain stabilizer can be adjusted with a wrench without disassembling the crank; The bottom bracket and crank need to be removed when installing the bottom bracket chain stabilizer. Specification: Material: Aluminum Alloy Size: 35mm-31.8mm/1.37-1.25inch(or E Type Installation Mount) Package Includes: 1 Piece Chain Guide 4 Pieces Washers 1 Piece Frame Protector Note: Color might be slightly different due to the color calibration of each individual monitor. Please allow slightly measuring deviation due to manual measurement.