MaterialHot water bottle is made of rubber to ensure maximum safety, waist cover is made of Flannel, can keeps the water warm for a longer time. Package Contents1x koala hot water bottle, 1x warmer cover hot water bag, 1x soft plush waist belt. Plush Waist Belt 112 CM/ 44 inch Length. For more details, please refer to the picture. CapacityHot water bottle with pouch capacity:1000ML, Wall thickness: 2MM, suggested to fill to 2/3. (Note: the temperature of the hot water should not exceed 80 degrees celsius.). Ideal GiftHot water bottles with covers with wide mouth, the hot water can easily to fill, comes with an anti-squirt stopper, safety and easily let water in and out, a must have gift for friends and family in cold weather. Wide Range of ApplicationsMicrowavable hot water bottle is good for relieving menstrual cramps, aching muscles and joints, arthritis, sports injuries. Hot therapy helps to relax your tired muscles and tensed shoulders from stress and too much workout.