This fiting has standard 1/8 inch NPT male threads on one end and then accepts a macro line hose. Macro line hose is the easiest hose to work with when running air for you marker. Cut the ends straight with a razor blade (not scissors) and slide it in to a Macro Line Fitting like this one. You"re good to go! Can be used for nitrogen, CO2, or HPA. If you"re using CO2, make sure to keep your equipment out of the sun. Prolonged direct sunlight can cause CO2 to expand beyond the pressure rating of macro line hoses. If you"re using macro line and CO2 it"s not bad to keep an extra hose on hand. Their easy change fittings make it it a snap to work with even if you do have a problem.