This genuine MTD reel and line assembly can be used as a replacement part for string trimmers. The function of a reel and line assembly in a string trimmer is to spool and unspool the line that spins and spreads out to cut grass, shrubs, bushes, and other such greenery.A reel and line assembly might have to be replaced if there is damage to the spool such that it cannot dispense the line from the string trimmer. This damage can come as a result of general wear and tear or a direct impact collision that warps the part and prevents it from serving its function. If this kind of damage occurs to the reel and line assembly, this genuine OEM replacement part should be ordered immediately. Remember to always wear gloves when handling, repairing, and operating outdoor equipment. This is an OEM part sourced directly from the manufacturer. It is sold individually. This reel and line assembly is compatible with the following brands: MTD, Ryobi, Yard Machines, Bolens, and Yard Man.