A replacement cover for the milk glass duck covered dish or container, originally made by McKee in the late 1800s, then produced by Kemple Glass in the 1940s from the original McKee mold. The duck has no markings and no fire or opalescence, so I'm pretty sure it's the later Kemple version. It measures 4-7/8" by 3-5/8" across the base and is in perfect condition with no damage.