Instant Hot Patch ThermaCare® HeatWraps Menstrual Pain Abdomen One Size Fits Most Nonwoven Material Cover DisposableThermaCare menstrual pain therapy heat wraps, with patented heat cell technology, provide soothing heat for 8 hours of menstrual cramp pain relief. They're thin and discreet enough to wear under clothing on the go or while relaxing. In a carton, there are four, one time use menstrual heat wraps which are air activated.