ITEM NAME:New Clutch Drum Sprocket Replacment Part 1123 640 2005 Chainsaw For Stihl img *{margin:0;padding:0;.Fits for Stihl 018 017 MS170 MS180 Chainsaw. Clutch Drum Sprocket: Pitch 3/8", Picco 6 teeth. New 3/8" 6T Clutch Drum Sprocket. 1piece Clutch Drum Sprocket. Replace part numbers: 1123 640 2005.