Skylink Rolling Code Technology. Works with most brands of garage door openers. Easy to install, no special tools required. Easy to program. Keychain style transmitter (long-life alkaline battery included) that goes with you. Compact-size dual button transmitter can operate two garage doors. (additional Garage Door Receiver 18R required for second door; sold separately) Transmitter can also be used to control plug-in lighting, fan or small appliances with SW-18R Wireless Switch Receiver (sold separately). FCC/IC approved. UL listed. One year warranty.