The measuring tubes are made of a thin glass tube that is fused at the ends. Inside, there is a chemically reactive filling layer. To take a measurement, the ends of the tube are broken off and the tube is inserted into the gas detection pump. By compressing the pump, the air to be tested is drawn into the tube, causing the filling layer to change color when it reacts with the corresponding gas. The concentration is read off an integrated scale. This hand pump is designed for use with the directly indicating Dräger tubes. It is easy to operate with just one hand and features an integrated tube opener and stroke counter. It operates without a power connection or batteries, making it suitable for use in EX areas.