The Testo 317-2 (0632 3172) Handheld Gas Leak Detector safely and efficiently tests gas pipe connections for leaks. This handy gas detector for new users detects two types of gas, methane and propane. The gas concentration is shown via a bar display. In addition, the gas leak detector indicates increasing gas concentrations via an audible alarm. The 317-2 Gas Leak Detector also confirms audibly that it is ready for measuring.