Advanced Photoelectric Technology, Accurate, Reliable and High Sensitivity:Our smoke detector is an independent photoelectric smoke detector. Photoelectric alarms are generally more effective at detecting slow smoldering fires and fast flaming fires Built-in 10-year battery:Built-in lithium battery with 10-year lifespan. No need to change batteries. And with a low battery warning alarm to remind you to change a new smoke detector to protect your family Easy to install and big test button: The smoke detector should be installed on the ceiling . And if the cooking fumes trigger a fake smoke detector, you can easily trigger it by pressing the big test button with a stick or something 85dB Loud Sound Alarm and Red LED Warning: L The smoke detector alarm sounds a loud 85dB alarm and the red light flashes quickly. To warn you there is a risk of fire