Beeswax Double Coated Black Plasticell is an Injected molded plastic raised cell sheet. Coated with 100% USA beeswax in Hamilton, IL to help the bees start drawing the cells. The best plastic foundation available. Tested and proven as the ultimate in plastic foundation. Precise deep cell walls. Uniform exact cells. Fits 9 1/8 inch frames Foundation size is 8 3/8 inches x 16 3/4 inches. Used with wedge top bar or grooved top bar frames. The black color helps beekeepers see the eggs in the cells, allowing them to watch the brood laying pattern of the queen.