Sleep in unsurpassed luxury with our ultimate goose down and feather mattress topper. The mattress topper is cassette chambered (with baffled - channelling) to keep it's shape and ensures the filling is evenly distributed all night long. Covered in a 100% cotton, 350 thread count downproof to keep the down and feather deeply encased.The mattress topper fits neatly over your mattress and under the base sheet.