Zip-Off Pillowcase: Made with durable, wrinkle-resistant polyester fabric, featuring a smooth zipper for hassle-free cleaning and replacement. It is non-pilling and can withstand multiple machine washes, maintaining good condition. Anti-Slip Design: Featuring plastic-coated bottom that fits tightly with the mattress, this mattress gap filler prevents sliding during sleep. It provides stable head and neck support, ensuring comfort whether side-sleeping or lying on your back. Versatile Use: This multifunctional bed gap pillow is ideal for filling bed gaps, adjusting sleep height, or offering back and leg support. It meets your diverse needs, ensuring comfort and convenience for sleep and daily activities. High-Quality 25D Foam: Made with soft, elastic 25D high-density foam, providing comfortable support for your head and neck. Its rebound ensures the headboard pillow keeps its shape after repeated use. Note: Let it rest for 48 hours to fully restore shape after unpacking. Multi-Function Gap Filling: This bed gap filler is especially designed to fill gaps of 0-4 inches between the headboard and mattress, preventing items and pillows from sliding off, keeping your bed tidy and organized.