- for gas test standpipe - safe device to prevent flame breakthrough into gas pipeline or gas tank - PTB 04 ATEX 4001 X, explosion group EEx IIG IIA (for example methane or propane) according to DIN EN ISO 16852 - can be used in gas standpipe with max. pressure of 20 bar - brass-made adapter with 2 1/2 internal thread/ext. thread (with sealings) for direct connection to the gas test standpipe