Honeywell's 5811 is the most discreet wireless door and window sensor available. When installed on a door or window frame, the Honeywell 5811 wireless thin window or door sensor is nearly invisible. The 5811 sensor protects a single opening from intrusion and when programmed to a Honeywell alarm control panel will use (1) wireless zone. We recommend installing the wireless sensor on the door or window frame and the included magnet on the actual door or window. The magnet needs to be installed next to the 5811 sensor along the side that has the (2) magnet alignment locator tabs and can be no further than 3/4" from the 5811 door sensor or window sensor. Use the included double sided tape for easy do-it-yourself installation. Mounting hardware is also included if you would like to make it a more professional installation.