Features: High reliability sensor to help you detect gas density, it can detect precise scope. Made of premium materials, safe and stable. It's durable for long time use. Sensitive and effective alarm function can decrease the phenomenon of false alarm. Low current consumption, ultra-long standy time, alarm memory function, low battery prompt, auto detect sensor failure. No radiation, it causes no harm for people who come close to it. Easy to install and operate. Quick reaction to save your family from the silent killer carbon monoxide. Detection of natural gas, liquefied petroleum gas, improve home kitchen security. Specification: Condition: 100% Brand New Material: Plastic Color: As Picture Shown Size: 12.5 * 7 * 4cm / 4.9 * 2.7 * 1.6in Power: DC9V battery Sensitivity / Alarm Time: Alarm Standard: UL (UL 2034) 70PPM, 60 to 180 minutes 150PPM, 10 to 50 minutes 400PPM, within 4-15 minutes 700PPM, within 2-6 minutes Alarm standard: EN (EN 50291) 50PPM, 60 to 90 minutes 100PPM, 10 to 40 minutes 300PPM, within 3 minutes 400PPM, immediately Alarm standard: CN CO concentration exceeds 150PPM within 5 seconds Quiescent current: <80uA (200uA when the LCD indicator is on) Alarm current: <30mA Working environment: 0-50 °C Ambient humidity: 10~95% R.H Alarm output: voice and red LED flashing alarm Static output: green LED flashes every 30 seconds Detection level range: 000~999ppm Sensitivity level: 5ppm Error: +/- 10% Normal working condition: 000ppm Alarm concentration: 030-999ppm Low battery warning: Sound "Please note, low battery warning", battery signal flashing (Battery is n o t included ) Package Weight: Approx. 157g / 5.5oz Package Included: 1 * Alarm 1 * Instructions Note: 1. Please allow 0.2 inch error due to manual measurement, thanks for your understanding. 2. Battery is not included.