Size: Total Length: 36mm / 1.42'; Inner Diameter: 8mm / 0.31'; Outside Diameter: 36mm / 1.42' Convenient to install: Easy to install but professional installation is recommended. Chain roller pulley slider complete with duty bearings ready to use. Necessary Function: The Pulley Wheel Roller can provide a smoother riding experience, which is useful, and a necessary accessory for motorcycles. Durable Material: Made of durable rubber and metal material, which is waterproof, hard resistant. Universal Fit: The chain roller guide is fit for most dirt pit bikes, street bikes, motorcycles, ATVs, off-road vehicles, etc.