8-3/8" Black Beeswax Coated Plasticell is an injected molded plastic raised cell sheet. Coated with USA beeswax 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" frames. Foundation size is 8-3/8" x 16-3/4". Used with grooved top bar frames.