Standard test equipment for gases 5 3 connections can be freely assigned 1 connection for natural gas 1 connection for 10 ppm CH4 1 connection for fresh air through an activated carbon filter and integrated electric pump, this fresh air is used for zero stabilization of the semiconductor sensor (10 ppm test). Pump and internal electronics are powered with 12 VDC optionally via car or power supply. Delivery includes power supply and fresh air hose.