Ease of use: Wide opening, making it easy to drink from, even for kids. Capacity: Holds about 500 ml of liquid. Waterproof: Increased watertightness. How Domyos accessories are created: Our entire range has been designed to provide you with the comfort needed to enjoy fitness sports. At Domyos our teams work together to design products that ensure your fitness sessions remain a relaxed and enjoyable moment. We want you to be able to forget about your gear and focus on your workout. Our models have been tested during use and we regularly make changes based on customer feedback.