As a homeowner, you should reset the opener to prevent outsiders from opening the door with a remote that's set to a Liftmaster default code. A simple procedure allows you to reset the opener for one or more remotes.
doorsill - the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway. doorstep, threshold. 1  doorway, room access, door, threshold - the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close; he stuck his head in the doorway.
Box Sill. A box sill is a type of sill which is used in framing. The box sill is nailed directly onto the floor joists. Onto the block sill is nailed the vertical header joist and outside and horizontal joists are nailed to the header joist and outside joist, comprising the frame on which the sub-flooring is attached. Box Sill for Platform Construction.