This complete line of all steel bodied valves with bolt-on bonnets are designed and built to maintain reliability both in their seating and back seating functions. This entire line is supplied with stainless steel stems and backseating 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 from 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. A packing nut design with either 1/4" or 5/16" flats provide a generous wrench engagement area, with little likelihood of "rounding" the flat. With the O-Ring cartridge used in all valve bonnets, there will typically be no need to loosen the packing nut when opening or closing a valve. In most cases, stem resistance will be negligible allowing the valve to be easily repositioned.