Down traps warm air and provides loft. Creates a lighter, softer and more comfortable mattress topper. 100% cotton 100 thread count cover. Elasticated corners to remain securely attached to mattress. Comes in five sizes - Cal King: 79" x 83" / King: 71" x 83" / Queen: 65" x 83" / Full: 60" x 79" / Twin: 44" x 79".