This OEM Hinged Mulch Plug Assembly includes both the plug and the spring. It is a black, plastic assembly which is rated as "Easy" to install, requiring a screwdriver, and socket set. This part seals the discharge chute to prevent the grass clippings from coming out. If broken or damaged from fatigue, it will not be able to contain the grass clippings and should be replaced. This part attaches onto the deck of the mower. Refer to your make, model and diagrams to ensure this model is correct.