Harris Premium Bed Bug Mattress Encasement Protector Cover - Twin Protects Against Bed Bugs, Dust Mites & More Waterproof - Protects Against Spills and Fluids Soft and Breathable Surface Prevents Heat Buildup Multi-Angle Zipper with Velcro Seals Tight and Stays Closed to Keep Bed Bugs Out 39" x 75" and Sides Expand Up to 14"