Thread Size : 0.3750-16UNJC-3B, Width Across Flats (in) : 0.675-0.691, Width Across Corners (in) : 0.763, Weight (lbs/100) : 3.8, Locking Insert : Red Nylon (350?F Max Performance), Performance : Locking Torque in Accordance withNASM25027, Series : NU, Thread Type : UNJC, Thread Notes : MIL-S-7742 or AS8879, Thread Squareness : ESNA Spec 405, Group I, Material : Stainless Steel, Material Rating : AISI 303 or Equivalent, Finish : Plain, Overall Height (in) : 0.532-0.562, Hex Height (in) : 0.392