15 X 21 * The Patented Gelly-roll Pillow Combines A Hollow Cervical Roll Filled With A Removable Gel Pack And A Standard Pillow * Soft Thick Fiber-filled Head Section Supports Head While Polyester Lined Cervical Roll Provides Added Support To The Neck * Retail Packaged * Heat Therapy: For Upper Neck And Shoulder Pain Place Gel Core In Microwave For 20 Seconds Then Reinsert Into Neck Roll * Cold Therapy: For Headaches Place Gel Core In Freezer For 1 Hour Then Re-insert Into Neck Roll * Fits Standard Pillow Cases *