Self Heating Knee pad Magnetic Therapy Knee Support Tourmaline Heating Belt Knee Massager Foot Care Tool. Tourmaline heating knee pad thermal Magnetic Therapy knee support Heating Belt knee Massager. Use twice a day, about 2 hours for each time (Do not use while sleeping). It is normal that some people with sensitive skin may feel burn or skin turns red. If it hurts your skin, you could shorten use time according to individual circumstance. You could also wear the brace through clothing but the heating effect will decrease and the magnetic effect will work as normal.