Our favorite bedding basics in dorm-friendly, extra-long sizes. Place our dreamy white mattress topper on a dorm room bed to add a luxe extra layer of support—and the comfort of home away from home. Covered in pure cotton with a twill weave, the extra-long twin topper has a generous depth of 2.5 inches. Edge-to-edge baffle box construction keeps the hypoallergenic fiber equally distributed.