Poweka 325"-7 Clutch Drum Sprocket, Clutch Cover Bearing Fit For Stihl 017 018 021 023 025 Ms170 Ms180 Ms230 Ms250 New high quality replacement parts It is 7 tooth. Fit stihl ms230 ms250 021 023 025 Fit stihl ms170 ms180 017 018 Package includes clutch drum + clutch sprocket