【Inner Thread】：M18*1.5- Air Outlets Thread: G5/8 - 4500PSI - Black Knob. 【Include】：Our diving valve is with sealing ring, good sealing,very suitable for use with diving cylinders. 【Used】：Standard for any 4500psi High Pressure Air Tank. 【Fit for diving tank】: Fit for high pressure cylinder.Both aluminum and carbon fiber cylinders are suitable. 【Advantage】: This inline valve are commonly used on Inspiration rebreathers. The valves have the bump guard on the bottom just like the original ones that come with your Inspiration Rebreather. These are your standard ¾ valves that fit aluminum tanks and steels.