Compatible With All Linear Access Control Receivers & ControllersThe Linear MegaCode Custom Coded Key Ring Transmitter is a remote keyfob used to control any Linear access control receiver or controller. The transmitter is preprogrammed at the factory in MegaCode format with one or four (select 1-channel or 4-channel) of more than 1,000,000 possible codes. For added security, the transmitter features a 10-second timeout to prevent a single transmitter from transmitting continuously. Works with Linear access control receivers and controllers More than 1,000,000 possible codes eliminate chance of duplication Includes quick-disconnect key ring Available Models: 1-Channel, 4-ChannelContents Transmitter Key Ring Batteries Security Products, Access Control & More By LinearFor more than forty years, Linear LLC has been known as a worldwide provider of radio based transmitters and receivers for the traditional security market. Millions of Linear transmitters have been sold over the years. Linear security products are offered via a worldwide network of distribution. While Linear continues to be a leading supplier of devices for the security market, we have expanded our products to include focused product lines in the Access Control, Remote Control and Garage Door Operator markets.