Magnitop plug that makes it work and seals water into the sink, it controls the operation in batch feed mode of the following models: Maxmatic 5000 Maxmatic 4000 (option) Maxmatic 3000 If you have a very old machine you may require the double magnet plug version, which we stock. If the new plugs don't work you have a problem with the sink outlet alignment which requires adjusting. See disposer fitting instructions. Includes Postage & Packaging