Combining beauty and practicality, this bottle is also eco-friendly because it reduces the usage of plastic bottles. Made from stainless steel and designed to resemble a bowling pin, each bottle is double-walled, keeping its content cold for 24 hours or hot for 12 hours! In other words, your little one can enjoy the water, tea, or any other beverage at the desired temperature on any occasion! Note: the lids of any bottle size are completely interchangeable.