Description: 【Quality Material】: This Mountain Bike chain guide is made of high strength aluminum alloy, which has heat treatment and CNC machining. It features a lightweight design and fine workmanship for durability and longevity. 【Compatibility】: The BB bottom bracket chain stabilizer is suitable for 30-40T round discs, making it versatile for various biking needs. 【Features】: Effectively prevents chain drop and chain jump, used for single piece sprockets; installation requires disassembly of the bottom bracket and cranks. 【Resistant】: Made from high strength materials, this bike Chain Protector is wear resistant and anti deformation, ensuring it can withstand the rigors of cycling. 【Note】: Applicable to threaded BB bottom brackets (press in type is not supported) Specification: Material: Aluminum Alloy, Nylon Size Chart: Box: 13.44cmx8.07cmx3.06cm/5.29inchx3.18inchx1.20inch Package Includes: 1 Mountain Bike Chain Guide  Note: Please allow slightly errors 1-2cm differences due to manual measurement.