Qiankun Stihl 017 018 021 023 025 MS170 MS180 MS210 MS230 MS250 sprocket clutch kit worm Quality Aftermarket parts, Non-original and Brand New Fits the following models of Stihl chainsaws: 017 018 021 023 025 MS170 MS180 MS210 MS230 MS250 Includes the following: Clutch assembly replaces OEM 1123 160 2001 325 pitch spur sprocket replaces OEM 1123 640 2015, 1123 640 2074 sprocket bearing e-clip washer worm gear replaces OEM 1123 640 7102