The design and purpose of the O-ring is relatively self-explanatory. It is an “O” shaped ring used as a gasket in lawn and garden equipment. It is designed to sit within a groove and be compressed during assembly. It creates a perfect seal that blocks the path of liquids or gases from escaping or flowing into regions of the machine where they are not supposed to be.The O-ring may be damaged if an outdoor piece of equipment is struggling to start or run. After checking the air filter cover, removing the carburetor, and cleaning it thoroughly, the next step is to replace the O-rings, carburetor gasket, and air filter, followed by the spark plug. Regular maintenance of the carburetor and routine evaluation of the suitability of the O-ring is essential to proper mechanical maintenance.This O-ring is a genuine OEM part sourced directly from the manufacturer, and it is sold individually. The manufacturer of this product is MTD. Examples of compatible products and machines includes trimmers, tillers, weed wackers, brush cutters, and leaf blowers or leaf vacuums. It is compatible for products made by the following brands: MTD, Cub Cadet, Craftsman, and Troy-Bilt.