This gas detector is essential for gas boilers (geyser), central heating boilers (gas heaters), open gas heaters & gas cookers. Alarms early after detection of leakage of natural gas. There is a recommended mounting height. This detector detects either methane gas or natural gas. These gases are used primarily at home. The danger of these gases is that they mix with air to become slightly inflammable. The tinest spark could then set off an expolsion. This detector has an adaptor power supply & operates on a mains voltage of 230-50hz. The detector is a stand alone alarm & is therefore not connected to another system. This detector does not work during a power failure. Do not connect to a switched socket. This gas detector is designed to detect natural gas. It is not intended to detect smoke, fire or any other gas. The gas detector only indicates the presence of gas in the vicinity of the sensor. The presence of natural gas in other areas of the house is not detected. Install the detector between 1 & 5 metres from a combustion source for example a cooker, boiler etc. Instructions included in pack..