Will not work on openers or remotes that end with a ""C"" used in Canada operating on 315Mhz. Features & Specifications Activates up to three one channel radio receivers or one 423LM 3-channel receiver. Red LED light indicates battery strength. Color coded buttons for easy identification. Visor clip included. Power: 12 volt battery included Frequency: 390 MHz Codes: 9-trinary DIP switch's with 19,683 combinations Dimensions: 3.5 x 1.6 x 0.6 inches