Head with four necks, three inline standard taper joints and one 90 degree joint. 10/30 size for use with our 8314 family of jointed thermometers. Use with our 6504, 6511 & 6516 reaction vessels that feature either a 137 x 100mm ID or 168 x 130mm ID flat flange. Use with our 6508 or 6510 clamps. For improved sealing of flat ground flanges, please see our 6495 product family of gaskets. Note: vessels with o-ring grooves seal with the vessel's supplied o-ring.