The Firefly 390LMPB2K is a 2-button keychain garage door opener remote engineered to work with LiftMaster Billion Code receivers operating at 390 MHz. Designed as a dependable replacement or add-on transmitter, it is compatible with LiftMaster, Chamberlain, and Sears Craftsman operators that use the Billion Code radio system identified by a green Learn button on the head unit or external receiver. Each button can control a separate door or gate on the same technology, making it practical for multi-door residential or light commercial applications. The Billion Code rolling-code encryption helps prevent code grabbing by transmitting a different identifier with each press.
Programming is quick: press and release the green Learn button on the opener, then press the desired button on the 390LMPB2K until the opener clicks or lights flash to confirm—repeat for the second button or additional operators as needed. This remote is not compatible with Security+ (red/orange or purple Learn button), Security+ 2.0/tri-band (yellow Learn button), or older DIP-switch systems. For best results, ensure the opener’s safety reversing system is installed and functioning, and test operation from a safe distance after programming. This LiftMaster Billion Code compatible remote offers a compact, keychain-ready form factor for everyday use and an easy upgrade path for replacing lost or aging transmitters.