WARNING?Please read the Instructions before installing and operating the product Accurate Sensitive: The smoke alarm adopts photoelectric technology to detect smoke. Keep your home safe Photoelectric Technology Material: Fire-Retardant ABS V0 Level. 9V Battery-Powered Photoelectric sensor Smoke Alarm. photoelectric technology which is optimized to detect slow smoldering fires which generate light smoke, little heat and may smolder from all directions for hours before bursting into flames. Test Button: Test smoke alarm every week by pressing the test button in the middle of the cover for 5 seconds. Please change batteries when smoke detector inform low battery, smoke alarm chirp every 32 seconds and the red LED flashes at the same time Sound LED Warning: If fire alarm detects smoke or combustion particles in the air, it will sound in 85db and red LED will flash rapidly to remind every member to check. If fault, please clean dust or smoke inside smoke alarm with fan Home Protection: According to US data analysis, a family fire begins every 38 seconds. The faster you know about the fire, the sooner you start moving your family, and the smoke alarm at work reduces the risk of home fire deaths by 50% 10 Years Warranty: If there are any problems with our products ,you can contact us ,we must reply you within 24hours as soon as possible.NOTE: Please test it once a month to ensure that the smoke alarm works properly. Please clean up the dust on the alarm every 6 months to prevent the smoke alarm from being clogged or blocked.