BrassCraft Mfg PS1087 Gas Leak Test Solution Seal N Check KIT Gas leak detection solution thick formula produces well-defined bubbles to clearly indicate a leak Non-toxic, non-corrosive to metals, plastic or rubber, it is water soluble Pipe thread sealant can be used with steel, brass and plastic pipe threads. Do not use on flare or compression threads Use with natural, manufactured and LP (propane) gas, as well as refrigerants and oxygen