This genuine MTD replacement part is a crankcase cover O-ring for use with trimmers, blowers, tillers, edgers, string trimmers, and cultivators. A properly functioning O-ring is essential for the safe and reliable use of the equipment. The crankcase houses the crankshaft, and the O-ring is used to ensure a seal on the case. A damaged or worn out O-ring may cause oil to leak, leading to unsafe operation. The O-ring may become worn out or damaged with extended use, necessitating replacement. Remember to check the O-ring periodically to spot any wear or damage. This part is an identical replacement for an O-ring that is missing, worn out, or damaged. Prior to working with this part, please refer to the original product manual for installation instructions. Additional tools may be required for installation of this part. For safety, always wear gloves and ensure unit is powered down prior to performing any installation or repair.This high quality OEM replacement part is sourced directly from the manufacturer, and it is sold individually. This part is compatible with a variety of Craftsman, Cub Cadet, Troy-Bilt, Yard Machines, MTD, and more trimmers, blowers, tillers, edgers, string trimmers, and cultivators.