A hot water bag is a fundamental heating device that serves as a natural method of pain relief and keeping the body warm. The basic apparatus is made of rubber, along with a plastic composite material. FAIRBIZPS Hot Water bottles were designed to give you exactly what you need, exactly when you need them. Using this generous 2-liter bottle–hot or cold– is the comforting, healing answer to the relief you crave. Plush comfort made for you. Our hot bag provides the perfect heat level and protects you against excessive heat. Perfect as a feet warmer or to warm your bed. Moreover, it can soothe menstrual cramps, neck and shoulder pain, stomach ache, muscle strain, and much more. We care about your well-being. HOW TO USE: Here is a step-wise breakup of how you should use hot water bags: 1. Hold the bag in an upright position. 2. Unscrew the bag and fill it up with hot water to a maximum of two-thirds of its capacity. 3. Using your hands, expel the excess air out. 4. Screw the stopper tightly. 5. Hold the bag upside down to check for leakage.