... /Optical Smoke detector/Smoke alarm,9V battery operated or DC 10- 32VMain Feature: Unique Light Labyrinth with High StabilityAdopted ... with Dustproof, mothproof, moisture proof, anti-white light, anti-electromagnetic interferences designSound &Flash Alarm, Low Voltage indication, Self-test Function, network ... area: 60 square meter (with 4 meter height)Alarm Sound Level: ≥85dB / mDimension: Φ120×45mm