Gas and Bung Wrench Non Sparking Solid Drum Bung Nut Wrench (BLUE) Back side of wrench used to open emergency gas meter shut off valves Handle bottom has two tools that look like a phillips and a straight. This can be used to open the 3/4" bung found on most smaller barrels. Most 15 gallon drums there is a larger 2" bung and a smaller 3/4" bung. Non Sparking Solid Drum Bung Nut Wrench