Straight Strain Relief Fittings Straight Strain Relief Fittings with Dome or Flex Nuts - Nylon DOME FITTINGS FLEX FITTINGS Longer thread lengths available in PG sizes The PG7 thread fits a 1/4" NPT or 1/2"-20 UNF. *Locking Nuts for fittings are sold separately. *O-Rings and Seals are also sold separately.