Utopia Bedding Premium Bed Bug Proof Box Spring Encasement - Waterproof Zippered Box Spring Cover - Knitted Box Spring Protector (Twin XL) The twin XL sized encasement measures 39 inches x 80 inches fits box spring up to 9 inches deep The high-end 100% polyester knitted fabric is soft, breathable and highly waterproof Stretchable and secured 360 degree by a mini-zipper with a zip guard that provides protection from even the tiniest of the bed bugs High quality stitching provides extra durability and makes it tear-resistant Machine wash on cold and tumble dry on low