FKM o-ring seal and PTFE back-up ring below the stem threads to protect from corrosion and galling; PTFE or Graphite packing optional.172" Orifice, Panel Mount (2 nuts) 100% helium leak tested to 1 x 10-4 ml/s for guaranteed performance and reliability.Mini Valve, Hard Seat, 1/4 NPT Female - 1/4 NPT Female, 316 SS, 0..