This aftermarket clutch assembly is just the ticket for those saws with burned out drive systems. This clutch assembly requires the use of a piston stop or air wrench to remove and install properly. Fits the following chainsaws:Stihl 017, 018, 019 T, 021, 023, 025, MS 170, MS 180, MS 190 T, MS 191 T, MS 210, MS 230, MS 250Replaces Part Number: 1123 160 2050