NOS Setting up a manifold for a Direct Port Nitrous Oxide System usually takes some time, skill and a welder. NOS have tried to help reduce the time and effort with a machined and threaded weld-in fitting. These fitting are made from 1/2" 6061 aluminum round stock, machined to 3/4" overall length with 1/16"NPT threads tapped into one end with a 0.250" through hole.