Eliminate the telltale signs that you have an alarm system installed. Unlike conventional contact switches, these switches are completely hidden. These Long Round Magnetic Contacts are 1.3 long and are ideal for doors. Each contact has an operational gap of one inch. Simply drill a 3/8 hole in the edge of a door or window jamb and press fit. The wires are can be passed through the jamb and framing and run over to the alarm system controller. Both the switch and wire are completely invisible when the door or window is closed. Mount the magnet in the door or window so that the two are in contact with each other when the door or window is closed. more info