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: 1Mountain Bike Chain Guide Note: Please allow slightly errors 1-2cm differences due to manual measurement.