The Deluxe Door Top Lock rests on top of the door so tots can't reach it. A peg mounts (screws in) on the door frame and the latch slides around the peg to lock and release. Perfect for interior basement doors or doors to the garage. Opens from either side of the door. Two easy grip wand extensions for both sides of the door for shorter adults. Fits all standard interior doors up to 1 3/8" thick. Not for use with exterior or over sized doors. See item GL-3 for thicker or exterior doors.