4 inch x 5 inch. Lasts up to 8 hours. Air activated. Safety tested. Multipurpose muscle & joint heat therapy. Odor free. Applies directly to skin. Mentholatum. Product is air-activated. Do not open until ready to use. WellPatch Warming Pain Relief Patch is a safe, odorless heat therapy that provides soothing relief from minor aches, pains, and stiffness of muscles and joints. This comfortable heating patch applies directly to the skin and can be worn unnoticed under clothing as you go about your daily routine. Questions or comments? Toll free 1-877-636-2677 Mon-Fri 9 AM to 5 PM (EST) www.wellpatch.com. Made in China.