Get current pricing for Oem, REGLASSED-36439-ID Reglassed 20 Top Head For A 20 Gallon Reactor. (2) 1 1/2 Flanged Nozzles (1) 2 Flanged Nozzle (1) 4 3/8 Peephole With Sight Glass . Product Category: Process Equipment, Sub Category: Process Reactors: