Water bottles are containers designed to hold liquids, primarily water. They come in various materials, including plastic, glass, and stainless steel, and are available in different sizes and shapes. Many water bottles are reusable, promoting environmental sustainability by reducing single-use plastic waste. These bottles often feature lids or caps to prevent spills and may include additional features like built-in straws or filters. Some are insulated to keep drinks cold or hot for extended periods. Popular brands like Nalgene and Hydro Flask offer a range of options for outdoor activities, sports, and everyday use.