This original STIHL muffler provides factory quality and ensures optimal discharge of exhaust gases, while at the same time reducing the noise level to the level prescribed by the manufacturer. Made of high-quality, thick-walled sheet metal resistant to extreme temperatures and corrosion, this muffler maintains ideal back-pressure in the cylinder. Correct back-pressure is key for two-stroke engines because it prevents loss of unburnt mixture and ensures maximum power, stable idling and optimal fuel consumption, which is the main advantage over cheap replacement copies. Before fitting the new muffler, be sure to clean the exhaust port on the cylinder of soot and carbon deposits, taking care that dirt does not fall into the cylinder. During assembly, be sure to fit a new original muffler gasket to prevent leakage of hot gases that can damage the plastic housing of the machine. Tighten the muffler bolts moderately and in a cross pattern according to factory specifications, and check their tightness after a few hours of operation, because initial loosening can occur due to high temperatures and vibration. Key characteristics: Part type/size: Muffler / noise silencer (Muffler) Manufacturer: STIHL – original part Reference OEM number: 4137 140 0600 Compatible models: Trimmers and brush cutters: STIHL FS 75; STIHL FS 80 / FS 80 R; STIHL FS 85 / FS 85 R / FS 85 T / FS 85 RX Telescopic saws and hedge trimmers: STIHL HT 70 / HT 75; STIHL HL 75 / HL 75 K Stock and availability of parts can be checked by sending an inquiry or by calling our phone number.