english ice cap bag is made of heavy-duty waterproof, rubberized fabric that keeps the ice cap cold and dry. Ice cap features an easy to fill large opening with plastic cap to keep ice secure and melt water inside the bag. Use this product after an injury to reduce swelling and decrease pain. Relieve pain andfort from bruises, muscle aches, swelling, headaches and more. Ice decreases blood flow to the injured tissue and reduces inflammation. Cold therapy generally works best when used for 20-30 minutes every 3-4 hours or until swelling goes away. Simply fill the ice cap with ice, close lid and apply to the desired location. Conveniently available in 9inch sizes.