3 3/4 x 5 1/8 Inch pads. Lasts up to 8 hours. Odor-free relief for stiff, aching muscles & joints. Air-Activated. Thin, comfortable & easy to apply. WellPatch Heat Warming Pad is a safe, odorless warming therapy that provides hours of soothing relief from minor aches, pains, and stiffness of muscles and joints. This comfortable heating pad applies directly to the skin and can be worn unnoticed under clothing as you go about your daily routine. Made in Japan.