Fire Alarm: Equipped with battery (not replaceable), using steel cylinder processing technology, can be filled with more positive and negative materials, more energy-saving, low-consumption and environmentally friendly. Easy installation: There is a smoke detector magnetic bracket in the package, and the smoke detector can be installed without drilling. Note: The installation position should fit the adhesive pad. If it does not fit, you need to use the included screw kit for installation. Mini Small Smoke Detector: The thinnest and most mini smoke detector, only 8.5 x 8.5 x 2.4 cm, can fit the ceiling perfectly . Flicker-free smoke detector: There is no annoying LED flickering in normal working mode, and the detector is especially suitable for use in bedrooms and children's rooms. [No false alarm smoke detector]: After tens of thousands of tests, it will only sound an alarm when the EU minimum smoke concentration standard is reached.