This is a grass catcher that attaches to the cutting deck of a number of walk behind lawn mowers. The bag fits over the metal bag frame, which is sold separately. The bag and frame are designed to detach easily from the mower so that grass clippings can be discarded quickly and the bag can be reattached. Although it is made of durable fabric, bags do become worn out. This is primarily a result of being dragged against grass, obstacles, fences, and other impediments. Once worn, the bags cannot be satisfactorily repaired and thus need to be replaced. Replacement is a simple matter of removing the fabric bag from the metal frame and slipping the new replacement bag back onto the frame. While making the replacement, it is a good idea to check the status of the metal frame, which can also become bent or even broken during normal use. When replacing this grass catcher bag, it is essential to avoid purchasing a generic, lower quality item. Instead, make sure to use a genuine OEM replacement part such as this one, which is manufactured to be identical to the original. This bag is compatible with mowers offered by Ryobi, MTD, Yard Man, Bolens, Yard Machine, Husky, Cub Cadet, and Troy-Bilt.