LiftMaster provides all the safety you need. The Protector System projects an invisible light beam across the garage door opening. If anything interrupts the beam while the door is closing, the door automatically reverses before making contact, If the beam is obstructed, the door will not close. Once your door goes down, it’s securely locked with PosiLock, a patented Chamberlain feature. An intruder cannot gain access. In a power failure, the manual release handle allows manual door operation. Please click here to return to our main Products Page.