A hot water bottle is a flexible container filled with hot water, designed to provide warmth and comfort. Typically made from rubber or thermoplastic, it can be used to soothe aches, pains, or simply to keep warm during cold weather. Users fill the bottle with hot water, seal it, and place it against the body for relief. Hot water bottles are often used in conjunction with other remedies, such as heating pads or blankets, to enhance comfort. They are a popular choice for people seeking natural ways to alleviate discomfort, making them a staple in many households.