Cylindrical filter reaction vessel body constructed with a top flange having a groove formed in the sealing surface of the flange and a flat ground flange on the bottom. Bottom flange is for connection to a CG-1949-F/CG-1959-F style filter bases. Top flange is compatible with any of the lids CG-1940 through CG-1946. For clamp see CG-141 or CG-141-T. For seals see CG-147 or CG-147-G.