- Equipped with photoelectric smoke sensors and electrochemical Japanese Figaro CO sensors that operate independently; detects dangerous smoke or CO concentrations in seconds with fewer false alarms - Provides 10 years of continuous power with a built-in lithium battery, saves energy and is environmentally friendly; no battery replacement required - Clearly displays real-time carbon monoxide (CO) concentration in the surrounding air, as well as remaining battery life and detector operating status when a CO concentration of 30-999 ppm is present for a specified period of time - Easily reach the test button for function test on the front/ alarm sound reaches 85dB/ 3-color flashing LED status light for more indicators (green LED normal operation; yellow LED battery low; red LED CO alarm) - This smoke carbon monoxide detector is BSI certified and complies with EN50291 and EN14604 standard.