Large sizes to meet the needs of use: 14.5cm. This size is suitable for children, youth, adult men/women, and the elderly. Largemouth cap design: leak-proof large mouth cap design is conducive to easier to put ice cubes, in addition, when hot compresses, the largemouth cap can also be better injected into the hot water to avoid hand burns. Note: Hot water should not be boiled for hot compress therapy, and it is recommended not to pour water hotter than 50C/122F works best. Safe & durable Largemouth cap design: leak-proof large mouth cap design is conducive to easier to put ice cubes, in addition, when hot compresses, the largemouth cap can also be better injected into the hot water to avoid hand burns. Effective hot & cold therapy: Cold therapy, adding the right amount of ice and water to the ice bag to relieve muscle aches, swelling, sprains, and the usual toothache, headache, etc. Hot therapy: hot water is added to water bags to relieve pain such as upset stomach, back, head and joints, etc. A must-have for home, outdoor & office: the hot and cold compress bag is lightweight, waterproof, foldable, and easy to carry. When you go out, you can use the injury ice pack to relieve pain when you sprain or falls.