Features: Mountain Bicycles Chain Guide ensures a stable and secure chain, preventing it from dropping. It is used for a single Chainring flywheels, and the running is more stable. Easy to install. It can adjusted with a wrenches without disassembling the Cranks. Make of Aluminum Alloys and steel materials, light weight, strong, wear resistant and resistant to deformation. Suitable for Mountain Bike, Road Bicycles. Frame of tube 34.90mm diameter convertible to a diameter of 28.6/31.8mm after installation. Specifications: Materials: Aluminum Alloys and steel Color: Black/Redness Size: as shown in the picture Package Includes: 1pc Chain Guide 3pcs Wrenches 2pcs Converter note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.