Featuring a center neck and two side necks with full length outer Standard Taper joints, this borosilicate glass 3-neck reaction vessel lid/cover has a flat flange. For use with large capacity cylindrical reaction vessels, 2000mL, 3000mL and 4000mL (LG-8082, LG-8084, LG-8085, and LG-8089). Flange diameter is 6-5/8". All sizes use LG-7316-108 clamps.