Therma Care Neck, Shoulder & Wrist is designed to pr you with instant pain relief for tight and tired muscles and can help restore them to their normal state. These discreet pads are worn under clothing and will pr therapeutic heat that lasts for up to 8 hours. They contain heat generating ingredients including; iron, charcoal, salt and water and can penetrate deep to relax tight muscles so circulation flows in. The constant heat pr d by Therma Care increases blood flow to tissues, giving pain relief which last even after the wrap has been removed. As muscles relax, more oxygen is pr d to the damaged tissues, helping to restore aching muscles. Key Features of Thermacare Back Heatwraps Patented heat cells for deep penetrating heat Therapeutic muscle penetrating heat Up to 16 hours pain relief when worn for 8 hours One size fits all Drug free relief from muscle and joint pain Contains 3 packs of 3 wraps (9 Heatwraps). Please note that results may vary.