This dorm mattress, with Performance Plus Nylon measures 36 inches wide by 80 inches long to fit Twin XL size beds. For use where firm support & durability are important, the Stellar Performance Core Plus Sleep System includes a revolutionary new, patented fiber that is used in a proprietary process to produce superior mattress quality. These premium mattresses are at the cutting edge of technology, manufactured with environmentally safe and 100% recyclable materials. The collection eliminates the need for steel innersprings and the entire sleep system can be recycled at the end of its life cycle, addressing ecological concerns in today’s market. The inner seam (bed-bug resistant) design has no tape edge, eliminating the main hiding place where bed bugs may reside and lay eggs and greatly reducing the risk of parasite infestation on the mattress. Complies with flammability requirements of CPSC 16 CFR Part 1633, CAL TB 129 and NFPA 101 Life Safety Code.