Part Number: 545171901 358350981 358350980 358350982 Compatible with Craftsman, Pou lan, Pou lan Pro, Hus qvarna, AYP, W eed Eater, Ro per and more. Compatible with Poulan: PP4818A, PP5020AV - 966807601 (2011-05) Compatible with Craftsman: 358350981 Chainsaw, 358350980 Chainsaw, 358350982 Gas Chain Saw Sprocket Clutch Drum: When the engine gets up to a certain speed the clutch will engage the Drum Assembly and the chain will start to spin. Sprocket Clutch Drum is part of the Drum Assembly, is the part that drives the chain. Excellent customer service: no matter when, if you have any questions, feel free to contact us, we will provide you with assistance, before buying, please double check your product serial number and the size is suitable, to avoid wasting your valuable time! Compatible with Craftsman, Poulan, Poulan Pro, HusQvarna, AYP, Weed Eater, Roper and more. Compatible with Poulan: PP4818A, PP5020AV - 966807601 (2011-05) Compatible with Craftsman: 358350981 Chainsaw, 358350980 Chainsaw, 358350982 Gas Chain Saw