Reaction Vessel Lid, 4-Neck, 29/42 Center Neck, 2-24/40 Side Necks, 1- #7 Chem-Thread Side Neck, 150mm Schott Flange. four neck vessel lid to fit CG-1920 through CG-1936 vessels. The #7 Chem-Thread will allow a thermometer or bleed tube having an O.D. of 4 to 7mm to be inserted vertically to the bottom of the vessel. Thread will accept CG-3504 adjustable immersion thermometers. Lid has a flat ground surface allowing it to be greased or used with an o-ring.