For existing working pipes (air, water, steam, natural gas, etc.), when you want to make a faster side connection (derivation) without cutting & welding, this part is THE SOLUTION.Iide (black rubber color), is a gasket piece in hard rubber, to close any leak. The only job is to perform a hole in the main pipe -by iide this piece- after mounting (check position, fix it by bolts, and it is ready)