Air-activated heat patch generates heats up to 40°C. The natural therapeutic heat will last for 8 hours& helps relieve neck pain and shoulder stiffness. Large size heat patch of length and width 13cm x 9.5cm can stick fitly and firmly around applied parts such as neck, shoulder or back. Effectively improve blood circulation, reduce symptoms of muscle fatigue, stiffness, neuralgia and muscular pain. It helps in recovery from tiredness. No fragrance or medicinal ingredient is formulated. Thin, odorless and simple design is convenient to put into pocket and bag, as well as enable the user to use anywhere and anytime.