These water cups are great for both school and recreational use. The retractable folding mechanism allows for easy transport and storage. They are easy to clean and dishwasher safe. The wavy edge rim acts as a brush rest that helps to keep the work area clean. These cups are an ideal accompaniment to watercolor pencils and the Connector Paint box. The water cups are made from a very strong, anti-slip material. For ages 3 and up.