The SUB-0 Degree SoftCell Chill pillow features a unique, customizable construction combined with the cooling benefits of PureCare's exclusive FRíO rapid chill cooling fibers. Clinically proven to cool 5x faster than traditional polyester, FRÍO fibers will help you find relief from sleep heat throughout the night. Explore the SoftCell Pillow: Reversible, 2-in-1 construction: Enjoy the plush comfort of down without the allergen drawbacks with our Identically Down-filled SoftCell pillow top. For a completely different feel, flip the pillow over for the reserved response of gel-coated memory foam. Adjustable loft: Easily adjust the height of the SoftCell pillow by inserting or removing the Identically Down pillow featured in the center of the pillow. All SUB-0 Degree pillows feature antimicrobial silver chloride to inhibit bacteria, mold, and mildew that cause deterioration, stains, and odors on this product.