This heavy-duty gauge extension is made of high-strength stainless steel and is rated for operating pressures up to 6500 PSI. It is far stronger than it would ever need to be and highly corrosion resistant. It's intended for use with the wide-bore gauge port we have listed. IT DOES NOT SEAL WITH AN O-RING AND HAS TAPERED THREADS, IT WON'T FIT DISCOVERY, MAXIMUS OR OTHER GAUGE PORTS THAT USE AN O-RING AND HAVE STRAIGHT THREADS. Military-grade thread-sealing tape about 3.2 mils (.032") thick should be used to seal the threads, we have that tape listed in full rolls and 36" sections.