This pillow features ventilated Gel Memory foam, which is a unique material that infuses gel particles into visco-elastic memory foam, creating a plusher and cooler sleeping material. In addition, this product responds to temperature and pressure to mold your shape by creating the perfect support for your head, neck, and shoulders. The Performance knit pillow cover is made from polyester fabric, which is designed to keep the surface of the pillow cooler. The fibers in the polyester fabric are shaped and formed by the specific " X " shaped cross-section that speeds up moisture absorption and diffusion.