Newton balance ball. ? contains 5 stress balls. ? it was made based on the famous scholar newton's laws of motion. ? no batteries required. ? its dimensions are 27x23 cm. ? it is a suitable gift option for special occasions such as birthdays, valentine's day, mother's day and father's day. it is also a suitable option for students. Improved version for clearer understanding and better search visibility. Suitable for users seeking detailed and reliable product information.