Compatibility And Fitment: 3/8 6T clutch drum sprocket kit compatible with chainsaw models 017 018 021 023 025 MS170 MS180 for MS 210 for MS 230 for MS 250, direct replacement for 1123 640 2003, designed to restore optimal power transfer and cutting performance Complete Kit Contents: Set includes 1 clutch drum, 1 needle bearing (10*12*10mm), 1 clutch washer, and 1 E-clip - everything needed for a full clutch system replacement, saving you the trouble of sourcing individual components Professional Grade Construction: Made from high-strength, heat-treated metal alloy that withstands high temperatures and friction, this clutch drum assembly delivers lasting performance even under heavy cutting conditions while maintaining proper chain tension Easy Installation: Precision-engineered to factory specifications for straightforward replacement without modification, this sprocket system features the correct 3/8-inch pitch with 6 teeth configuration that maintains proper chain speed and cutting efficiency Enhanced Performance: Upgraded needle bearing design reduces friction and heat buildup during operation, resulting in smoother chainsaw performance, improved fuel efficiency, and extended engine life while avoiding premature wear on your power tool