K5CO Carbon Monoxide Sensor, equipped with an electrochemical sensor from Kidde, guarantees a lifespan of 10 years. The battery power supply allows for optimal placement of the detector in the room and provides protection even during a power outage. Exceeding the permissible CO level is indicated visually (red LED) and audibly (loud, pulsing alarm tone at a strength of 85 dB). The device's memory stores information about the detection of a CO concentration that exceeds 100 PPM, allowing the user to ensure that no carbon monoxide is emitted in the room during their absence. The sensor features a test/reset button that allows you to check the device's operation and reset the alarm signal. The efficiency control system continuously monitors the sensor, internal circuits, and battery condition. In case of a malfunction or weak battery, the yellow LED blinks and an acoustic warning signal sounds. Additionally, the sensor is equipped with a function that allows you to quickly verify the correct response of the sensor to the CO test gas. Thanks to a specially designed housing, the sensor can be placed not only on the wall but also on a flat surface, such as a nightstand next to the bed. After 10 years from the activation of the power supply, the sensor reminds you to replace the device. The K5CO is marked with the construction sign B, confirming compliance with the Polish standard PN-EN 50291-1: 2018 + AC 2021 for carbon monoxide detectors in homes. The research was conducted by the Science and Research Center for Fire Protection of the National Research Institute. Furthermore, it has a BSI certificate confirming compliance with the requirements of BS EN 50291-1: 2018, issued by the British Standards Institution.