Features: *Wireless connection, the 433Mhz ES-D5A is installed in a few minutes. No need to run cables across your house to connect the detector to your alarm system: the detector is securely connected by radio-frequency. *The Etiger ES-D5A must be installed as the instructions, and can only detect for smoke (not combustible fumes, temperatures or flames). *Exclusive smoke intelligent algorithm, high sensitivity, no false alarm, strong anti-interference.No wiring needed. *Anti-light, Moth-proof, Dust-proof, moisture-proof, High stability. Low power CMOS microprocessor, effectively extend battery lifespan. *Once triggered, light will flash with loud high volume alarm sound, louder than 75dB.