Model Number: HM-621THS-#9785 Brand Name: HEIMAN Key Specifications/Special Features: * MCU processing* Low power consumption design, battery used for over 3 years* On-top battery compartment, easy battery replacement* Tamper resistant pins for battery* Low battery warning* Shockproof design, suitable for vehicle use* Auto check, malfunction in smoke chamber* Test and hush function* Auto reset Model number HM-621THS Operating voltage 3V DC (2*1.5V AA alkaline batteries) Static current ≤10μA Alarm current ≤25mA Alarm output sound and flash alarm Sending frequency N/A Interconnection N/A Sensitivity 1.8%/ft ±0.8%/ft/150PPM ±50PPM Sound level 85dB/3m Warm-up time 3 minutes Hush time 10 minutes Installation wall or ceiling mounted Working environment -10 to +50°C, 5-95%RH Dimensions φ110*45mm