Hot or cold get relief with our special Hydro-gel filled wraps for your sinus and head. Semi-solid glycerin/water based gel molds to your form and maintains its shape. The solid gel can`t leak even if punctured. To use as a moist hot wrap, heat in the microwave for 1-2 minutes and feel relief for up to 30 minutes. Freeze and get 30 minutes of flexible, therapeutic cold that reduces swelling and pain. Hand washable covers are made from unbleached cotton twill. Will last you a lifetime. Give yourself the care you deserve. One size fits all.