Linear ACT-21 - MegaCode Key chain Garage Door Transmitter

Linear Moore-o-Matic MegaCode format 1-button mini key chain size (2"x1") transmitter for gate or garage door openers. Smart coding system, no dip switches, 318 MHz frequency, 3 Volt lithium button cell batteries and a key ring included. The batteries should last up to five years with normal use. Compatible with all Linear MegaCode System products. Compatibles: Linear ACT-22, Linear MDR, Linear MDT-1, Linear MDT-2, and Linear MDTK.