Techko"s S090 Magnetic Sensor Entry Alarm is solar powered and can provide valuable protection for your home or property by detecting the unauthorized opening of a door or window, in a low-profile design. This alarm is designed for use on window or glass doors facing the sun (best with non-tinted glass). When the door or window is opened, the alarm"s switch detector sounds the built-in 90 db alarm immediately. The S090 and magnet adhere with double sided tape (included). To arm or disarm the system, there is a convenient slide switch on the side of the unit. Built-in 90 db alarm with high / low adjustment Powered by rechargeable Ni-MH batteries (included) For use on window or glass doors facing the sun Low battery LED indicator