The advantages of this product: -The digital billposters indicates the level peaks of carbon monoxide detected.-Easy installation and easy maintenance.-Test button. This Carbon monoxide detector powered by batteries uses leading edge electronic components to protect you and your family, from the danger of the CO. Its unique characteristics include a digital display which indicates the concentrations of CO in ppm (parts per million) as well as the levels of the highest CO. About the carbon monoxide: The carbon monoxide (CO) detector is a sophisticated device which was carefully conceived and tested to detect CO's accumulation in the residential environments. This detector is specifically reserved for a domestic use. Invisible, odourless and tasteless, CO can be deadly. CO's accumulation in the blood, called rate of Carboxyhemoglobin, prevents the body from stocking up normally with oxygen. According to its concentration, the carbon monoxide can kill in just a few minutes. The most frequent sources of carbon monoxide are defective or badly used devices of heating or gas cooking, the engines of vehicles, electric generating, chimney or blocked chimney duct, the fuel-fired heaters, the homes chimney, the thermal tools and the use of a steakhouse in a closed space. The poisoning to the CO appears by similar symptoms to those of the flu but without fever, but also by other symptoms as:Dizzinesses, exhaustion, weakness, headaches, nausea, vomits, sleepiness and confusion. No life will be spared by the dangers of the CO but the unborn children, the young children, the pregnant women, The old persons and the persons suffering from cardiac or respiratory problems may feel faster symptoms .one time a year, it is advised to control and clean the systems of heating, air conditioning, fireplaces and conduits by a qualified technician (for the gas as for the solid fuels).