The Model MDT-4/MDT-4A 5-Channel garage door remotes is designed for use with Linear's access control products. The Model MDT-4A is five-channel device. Pressing one of the remotes front buttons sends channel one through four. Pressing the small button on the remotes top sends channel five. The top button can be hidden with the top button cover supplied. Also included are lithium batteries with a five-year service life and a visor clip. The remote is MegaCode format, which means each remote is factory preprogrammed with one of over 1,000,000 codes, virtually eliminating the possibility of code duplication. Because the receiver learns each specific code, no unauthorized person can gain access to the system by reprogramming a remote. Features include it is compatible with all Linear access receivers and controllers, superior transmission range, factory programmed MegaCode format supports over 1,000,000 codes, unique Extra top button, high visibility operate LED, visor clip included, two