I was recommended to buy this by my child's special education teacher. 45 cm, suitable for heights of 120-150 cm. There is some dark staining, so please check before purchasing. Everything in the photos, including the air pump, will be included. From the product website: A very durable footed balance ball made of the same material as the Gymnic balance ball. When not in use, you can place your feet on the bottom, which is very convenient as it prevents rolling. It is used in the same way as a Gymnic balance ball. It can be used for a wide range of purposes, such as relaxation, stretching, training, or as a substitute for a chair. Using it as a chair in a school classroom or at home can naturally help you maintain good posture. The colorful colors are very popular with young children. Recommended for children. ≪Certified by NPO Japan G-Ball Association≫ ≪Certified by the Japan School Physical Education Research Federation≫ ≪Certified by the Japan Society of Gymnastics≫ ☆Material: Non-phthalate PVC Gymnic products are the only balance balls, yoga balls, and fitness balls that have passed the rigorous German TUV-GS test.