Model: HF S2E * Detection Technology: Photoelectric smoke detection * Alarm Sound Level: ≥ 85 dB @ 3 m * Battery Type: AA x 2 (included) * Battery Life: Approx. 3 years * Alarm Types: Low battery alarm, dirt filter alarm * Test Function: Self-test supported * Silence & Reset: Supported locally * Operating Temperature: -10°C to 55°C * Humidity Range: Up to 95% non-condensing * Dimensions: 123 x 121 x 73 mm * Weight: 161.4 g