The JA-151 ° detector uses wireless communication and is powered by three AA batteries. The detector should be installed by a qualified technician with a valid certificate with valid supplier.The detector indicates a fire hazard using the built-in LED indicator and audible signaling.The JA-151a is constituted by two independent detectors - an optical smoke detector and a heat detector. The optical smoke detector works on the principle of scattered light. It is very sensitive to large particles of dust that are present in dense smoke. It is less sensitive to smaller particles generated by the combustion of liquids such as alcohol. That's why the detector also contains a built-in heat detector which has a slow reaction, but it is much better at detecting fire which generates only a small amount of smoke.