3 Heat Patches 3.75 x 5.125 inch. Soothing heat lasts up to 12 hours. Applies heat to area of discomfort. Discreet and odorless. The Playtex Heat Therapy Heat Patches provide soothing relief of minor menstrual cramps and associated back pain. Convenient, discreet and easy to use, these air-activated heat patches are odorless and disposable. Made in Japan.