Increase security to entryways at home or in the office by installing the Enforcer Flush-Mount In-Wall Photoelectric Beam Sensors. Designed to fit into a single-gang box for a flush mount application, these sensors will not only be attractive, they will not stick out from your wall as other similar plug-in modules will. Beam alignment is adjustable up to 15 degrees horizontally or vertically, making installation even easier. A typical application for this product is to set the beam up across an entryway or hallway in your home, office or retail shop. When the beam is broken, the the sensors will turn the yellow LED lights on and trigger a normally closed, normally open or common relay output on your alarm system or warning device. This product requires a 12VDC Power Supply, sold separately.