This listing is for one brand new 6061 aluminum CGA680 nut and nipple.  This fitting is commonly used for nitrogen tanks, or other inert gasses and sometimes high pressure compressed air.  This fitting is good for a maximum pressure of 4000psi.  Perfect for 3600psi tanks. The end of the nipple has male 1/4" NPT RH threads.  Please make sure your valve is a CGA680 before you buy this item.  Thank you.