3/4" Inline Compressed Air Filter Desiccant Dryer Moisture Separator Trap Combo Inlet / Outlet: 3/4" Female NPT (measures about 1" diameter) This is a directional flow unit that comes which markings showing how to install. 3 Stage Compressed Air Filtration 5 Micron (Removes Water Droplets / Debris) .01 Micron Oilesser (Removes Finer Droplets / Oil Droplets / Oil Aerosol) Desiccant Dryer (Removes Any Remaining Moisture / Vapor)