"STEEL;3.990 IN. O/A LG;1.000 IN. HEXAGON HEAD,ONE 0.375-18NPT THD HOLE 0.875 IN. DEPTH THRU FLATS,ONE SLOT 180 DEG FROM THD HOLE 0.060 IN.W & 0.162 IN. DEPTH FULL LG OF FLAT;250-18 NPT,0.500 IN. THD LG,W/MALE HEX WRENCHING FEATURE IN CENTER,0.750 IN. W ACROSS FLATS"