This NAL Chuck was designed specifically to accurately adjust pressures through a shock schrader valve. The mini "T" handle opens and closes the center pin valve while it is attached to the valve stem so the pressure set is the pressure you get. This is the same chuck that we use on our #SIG-560 and #SIG-500 shock inflators. Rated for 1700 PSI. Stainless Steel. 1/8" NPT thread. Used for nitrogen shocks, Aviation applications.