LINEAR Megacode Garage Door Openers MCT-3 Three Button Remote Control Activates three MegaCode garage door opener receivers. Compatible with all Linear-MegaCode door operator systems, including LDO33, LDO50, LSO50 and LC075 series openers. Smart Button coding . 318MHz frequency. Dimensions 2 1/2" x 2 1/2" x 1 1/2". Battery, visor clip, and instructions are included.