Elegant, lightweight, battery-powered CO detector provides long-term protection against the hazards of deadly carbon monoxide as well as continuous monitoring of CO concentration, the sensor with a lifespan of 10 years will last longer than most other CO detectors. Continuous monitoring of carbon monoxide concentration. Digital display clearly shows carbon monoxide concentration. Peak value display - to display the highest recorded CO concentration between 11-999 ppm. Tested and approved for use in boats and caravans. Multifunctional green and red LEDs to indicate power and alarm status. Signal at the end of the service life alerts the user to replace the detector after 10 years. "Test/Reset" button to check the alarm function regularly. Battery Operated - 3 x AA Alkaline Batteries Included BSI certified to EN52091 part 1 and part 2 (motorhomes and boats) CE tested and certified.