Fits GY6 50cc 4-Stroke 139QMB Engine With Long or Short Case 22 Splines Inside The Clutch Drum/Bell??ID of Spline Area: 12mm OD of Drum: 115mm ID of Drum: 105mm Pulley Diameter: 118mm Product Description AH is specialized in providing parts and accessories for Off-Road Motorcycles, Karting, ATV and Scooters/E-Scooters We are your one-stop-shopping choice from replacement parts to Plastic Body Fender Kit accessories. Always ready to meet the end of Motorcycle & Powersports Lovers. We supply parts to support ranges of models and constantly update the catalogue to fit the latest product. We offer unconditional services for our product and are ready to provide you with the best pre-sale/after-sale service. A big part of the story between us would begin with a small part.