HIPA 49mm Cylinder Piston Bearing with Fuel Tune Up Kit for STIHL MS390 MS310 029 039 Chainsaw Cylinder diameter: 49mm Fitment models: STIHL MS390 MS310 029 039 chainsaw Package include: 1pc cylinder, 1 piston, 1 pin, 2 piston rings, 2 clips, 2 crankshaft bearing, 1 piston needle bearing cage, 2 oil seal, 1 air filter, 1 fuel filter, 1 fuel line, 1 oil line, 1 oil filter, 1 spark plug The cylinder has a decompression hole, if your original cylinder does not, please don't buy.