NIPPLE, 2 1/2" x 1/4" NPT Male - HELIOX - Medical Breathing Mixtures; CGA 280 Hex Nut, Medical Breathing Mixtures - HELIOX CGA 280 Cylinder Gas Connection - 0.750-14 NGO, RH-INT Thread - .750-14 NGO, RH-INT Thread - 285 - For use with Nut part number 284