Allows you to still come & go through your garage door, when the power goes out
Lift master 485lm battery backup system - chamberlain part number 4228- 100% OEM
New production dates- LiftMaster factory supplied
Also works with sears and home depot garage door battery back ups- replacement part
Compatibility for all battery back up units with slide in battery - 385/855 and new models
Easy DIY- Battery Replacement Instructions 1. Disconnect power to opener. 2. Using a Phillips head screwdriver, remove the battery cover on the motor unit. 3. Remove old battery and discard. 4. Partially insert new battery into motor unit with terminals facing out. 5. Connect red (+) and black (-) wires from motor unit to corresponding terminals on battery. 6. Replace battery cover. 7. Reconnect power.