BrassCraft Seal n Check Kit contains 3 mil tube of pipe thread sealant and 3 mil tube of leak detection solution (fluorescent green). Pipe thread sealant can be used with steel, brass and plastic pipe threads. Do not use on flare or compression threads. Leak detection solution is ideal for identifying leaks in natural, manufactured and LP gas connections as well as refrigerants and oxygen. Formulated to be non-corrosive to metals and safe on polyethylene pipe and fittings.