Chime Entry Alert Designed for Closed or Open Doors. The SL-40 is a battery operated stand-alone unit. Welcomes with a pleasant chime every time a person enters the designated detection area. The SL-40 motion detector features state-of-the-art passive infrared (PIR) sensor technology. PIR is designed to detect infrared energy emitted by the human body, when in motion, inside a given detection area. The AC-100 is not affected by car headlights, sunlight, reflections, colors or shadows. Operates with a door open or closed.

Every retail shop should have one of these.

Great for home back doors or front doors in any room.