This gas detector Gas-Pro-2 can gauge with its sensors a maximum of five different gases (CO / CO2 / H2S / O2 / CH4). Because of this versatility, the gas detector Gas-Pro-2 is ideal for use in a variety of applications, such as: near canals, sewage treatment plants, drains, wastewater facilities, dumps/landfills, chemical/oil plants, shipping ports and more. During the development of the gas detector, the engineers particularly paid attention to small dimensions, to simple handling with only one key button and to providing clear readability even in small spaces. By means of the "top mount display," these goals are reached even if the gas detector Gas-Pro is worn close to the body. A single-key handling of the gas detector with a click and a double-click is very expedient and supports a simple navigation through the menu even while wearing gloves. An additional unique highlight of this gas detector is the "Positive Safety" display. A three-colored LED beneath the display makes it easy to recognize the mode the gas detector is in. Green lights indicate "gas detector OK", yellow lights demand an inspection of the gas detector, i.e., a maintenance or a calibration, red lights indicate not to initiate the gas detector and to deliver it to maintenance or repair services. This "traffic lights" principle makes  it easy to understand, even for inexperienced workers in regard to initiation vs. default. The pre-alarm and main alarm is indicated acoustically (95 db), optically by means of two LED lights that are recognizable from any sight angle and supported by a vibration alarm. A pump to suction the gas can be integrated into the rubberized anti-shock enclosure of the gas detector Gas-Pro despite of its small dimensions. A suction pump integrated in the gas detector (Gas-Pro-1 and Gas-Pro-3 only)initiates by connecting the suction cap through a reed contact. The gas detector Gas-Pro operates with fully charged batteries for approximately 19 hours without pumps or 17 hours with initiated pumps. The collected gas concentrations during operation are saved every 10 seconds in an internal data storage. The measuring values the last 1000 events (initiation and shutdown, main and pre-alarm, calibration and e.g. measuring range transgression) are saved at the internal data storage as well. Thus, the collected data can be transferred from the gas detector to a computer by means of an interface cable, docking station with interface or a calibration station. To attach it to work wear, the gas detector is equipped with a stable alligator clip and an eyelet.