Product Name: C9 White Battery Operated Wireless Smoke Detector Alarm Model NO.: LM-101LD Infrared Sensor Installation: Ceiling Types of Smoke Detectors: Photoelectric Smoke Style Type: Smoke Detectors Trademark: C9 Specification: White Origin: Zhejiang, China Product Description Theunitis 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 devicedoesnot contain the radioactive material which is harmless to the environment.