Thin and easy to apply, these extra-large adhesive patches provide up to 8 hours of targeted, soothing temporary relief of back pain, muscular aches, joint stiffness, strains and sprains. Extra-large, comfortable to wear, these odourless patches apply directly to the skin and can be worn under clothing to provide all day relief. deep heat patches work by increasing blood flow to the affected area providing more oxygen and nutrients to aid the healing process and helps restore movement. Product is air activated once protective film is removed from patch it activates from 60 seconds to provide relief for up to 8 hours. Size: 26.5 cm x 9.5cm