This complete line of all steel bodied valves with bolt-on bonnets is designed and built to maintain reliability both in their seating and back seating functions. This entire line is supplied with stainless steel stems for maximum corrosion resistance and back seating capability. A unique carbon filled PTFE seat is standard throughout the line, lending durability to the seating surface. In addition, a dual O-ring stem packing design along with a stem packing seal is standard on all valves 1/4" thru 12". This innovative design seals both the valve stem and bonnet bore with independent O-rings, which are captured in a carbon PTFE carrier. The addition of the packing provides for backup sealing capability in the unlikely event of an O-ring failure.