Can effectively help to relieve local fatigue and pain Knee Heat Pads Reusable Thermal Therapy Knee Brace Self-Heating Knee Pads With Mugwort When To Use Heat After Knee Replacement While this heating pad gets HOT, you don't have to worry about getting burned (the last heating pad I had- I got some serious second-degree burns and bad blisters). There are three heating levels. Please see the photos of the timer- it is pretty simple to use- low, medium, and high