For kids, it is really difficult to learn the importance of teamwork from textbook. however water roller is a great tool to let kids learn how amazing teamwork is. it will be an amazing experience for 2 to 3 people together to get the roller rolling properly. our Water Roller Ball is made of imported thick high strength transparent coating PVC or TPU polyether materials, design of the three air chamber, ensure the gas chamber leak drum not sink, each end of the gas chamber force is 400 kg. It can take 2-3 people at the same time. Both sides are fully ventilated.there is no worry about tourists playing too long by obstructed breathing problems. our product is Ideal for any swimming pool, inflatable pool or lake.