· Surrounds the box spring on all 6 sides with a durable high-grade polyester surface material· Exclusive Micro-Zipper technology.· 360 Secure zipper feature prevents accidental openings by sealing the end zipper traveler with a Velcro flap· Polyester· WATERPROOF - Don't worry about your box spring getting ruined. Our box spring encasement protects agains liquids