20 tooth, 45 mm outer diameter starter gear for 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engines This starter gear is used on a wide variety of scooters and ATV brands and models that have Chinese built 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 enginesDescription 20 tooth, 45 mm outer diameter starter gear for 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engines. This starter gear is used on a wide variety of scooters and ATV brands and models that have Chinese built 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engines.Please check the dimensions on the Specs tab to see if this is the correct starter gear for your Chinese built 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engine. WARNING California Residents: Proposition 65 Warning Specifications Inner Diameter (tapered): 16.6 mm – 19.6 mmOuter Diameter: 45 mmNumber of Teeth: 20Thickness: 9.85 mm