The muffler on lawnmowers prevents neighbors from becoming overly upset when the grass is cut early in the morning. When the engine starts on the lawnmower, the combustion releases burnt gas, making a very loud noise. The muffler dissipates the noise to make the lawnmower run more quietly. Over time, heat from the exhaust and constant exposure to the elements may cause the muffler to rust and possibly have holes that increase the noise. If this happens, the muffler should be removed and replaced to keep the noise to a minimum. Wait for the engine to cool so that the muffler is cool to the touch. Wear work gloves and have a socket set and adjustable wrench available. Remove the muffler screws and set them aside to use on the new muffler. Remove the damaged muffler from the mounting bracket. Install the new muffler on the mounting bracket using the mounting screws from the old muffler. Tighten the screws and start the lawnmower to ensure the muffler is installed correctly. This muffler is a silver metal part that is sold as one unit. It does not come with attachment screws. It is designed for use on lawn mowers manufactured by MTD, Ryobi, Yard Machines, Bolens, Yard Man, Troy-Bilt, and Husky.