The best moist heat pad on the market. What's special about this pad? It produces its own moisture automatically, without adding water! A special flannel cover retains moisture for deep tissue therapy. The Thermophore Pack is manufactured with a momentary switch which has a feature-light touch for those with arthritic hands. The momentary switch turns off if the patient falls asleep using the product! The 4" x 17" size has VelcroŽ added to wrap around neck or face.