This convenient and energy-saving carbon monoxide detector is recommended for campers who are looking for peace of mind when planning to set up camp with the use of an internal fire Woodburning Stove. The precise electro-optical sensor means that you can keep abreast of the level of carbon monoxide by the digital display detector which is always monitoring your camping safety. KEY FEATURES: Working voltage: 3 AA batteriesAlarm sound: Greater than 85dBAlarm concentration: 50PPM 60-90 minutes alarm100PPM 10-40 minutes alarm300PPM 3 minutes alarmSize: 100 * 38mmPackage Included:1 x Carbon monoxide alarmNote: 1. Please allow slight error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same item color displayed in photos may be showing slightly different from the real object.