Smoke Sensor Alarm With 9V Backup Battery 10 Years

Product description: The unit is a photoelectric smoke alarm device. With the photoelectric technology, it is more sensitive to detecting slow smolder fires which general thick, black smoke and may smolder for hours before bursting into flames. The smoke alarm device does not contain the radioactive material which is harmless to the environment. A DC 9V External battery and warns you when the battery is low With the increase of working time,the alarm detection signal will be decayed, when attenuate to the certain value, the alarm will send a fault signal, you must replace the product immediately. Product design of the test function by pressing the test button, used to test the product is working normal. A weekly test is required.