This pillow has a removable gel core that delivers hot or cold therapy to relieve the pain of headaches, stiff joints, or sore muscles. The gel cylinder can be cooled in the freezer (for treating tension headaches) or heated in the microwave (for soothing sore muscles in the neck, shoulders, and upper back). The soft polyester fiber pillow's moldable core adjusts to the contour of your neck and the firm ends of the cervical roll help maintain correct sleeping posture. The hypoallergenic pillow is washable and may be used with standard pillowcases. Made in U.S. 21" L x 16" W x 5" D. (3 lbs.)