Standard-Store Custom Cool Golf Ball Art Zippered Pillow Cases Covers Standard Size 20"x30"(twin sides) Designed to add sophistication and style to your bedroom. Comfortable and 100% Brand New. Made of 50% cotton, 50% polyester. Best choice as a gift. It is zippered pillow case, with a zippered opening on the side. Standard-sized pillow covers that help to extend the life of your pillows.