Security+ technology, replaces pre-1983 receivers with discontinued transmitters. Easy to install, simply use your existing wall buttons' wires and plug into a wall outlet. The code between the remote and receiver changes with each use. Over 100 billion possible codes using Security+ remotes, however, this item will accept ALL older remotes as well. Accepts multiple remote controls utilizing up to 8 functions, and one Security+ keyless entry. Works with older Liftmaster, Sears, Craftsman and Chamberlain remotes.