The LiftMaster 333LM is a three-button Open/Close/Stop handheld remote transmitter designed for commercial and industrial overhead door operators that use LiftMaster Security+ rolling code technology at 315 MHz. Purpose-built for dock doors, warehouses, and other commercial applications, it lets a user command a single operator with distinct Open, Close, and Stop functions from a distance, providing convenient, secure radio control without running additional control wiring. As a Security+ device, the 333LM transmits a new encrypted code with every press to help prevent code capture and unauthorized access.
This Open/Close/Stop remote is compatible with LiftMaster and Chamberlain commercial operators equipped with a 315 MHz Security+ radio receiver that supports discrete Open, Close, and Stop inputs. It pairs through the receiver’s Learn function or per the operator’s programming steps; some installations may require adding an external 315 MHz Security+ receiver (for example, a compatible LiftMaster commercial receiver) if the operator does not have built-in radio or does not natively support separate O/C/S commands. It is not compatible with Security+ 2.0 systems that use the yellow Learn button or with legacy 390 MHz or DIP-switch radios. Always ensure the door system meets UL 325 requirements and that appropriate monitored entrapment protection is installed when enabling remote Close operation. This 333LM remote is a practical replacement part or upgrade for commercial LiftMaster setups needing reliable, dedicated Open/Close/Stop control at 315 MHz.
