A. Product - Size: 33 cm - Colors: Pink, gray, blue - Material: PVC - Package contents: 1 yoga balance cushion, 1 air pump, 1 ball needle B. Relieve back pain: Core training can help build a stable core. Strong muscles in the core area of the body are an important factor for relieving back pain. The ball seat cushion is a suitable training tool for exercising the core muscles of the body. C. Enhance strength through instability: The balance cushion may continuously produce a sense of instability during use, which will force the internal muscles to stay active and thus get exercised. The degree of instability can be controlled by adjusting the inflation volume with the attached air pump. D. Versatile use: From the classic use as a ball seat cushion on an office chair to a training equipment for functional training, this cushion with bumps is suitable for various kinds of people from beginners to advanced users. E. Equipped with an air pump: Each ball seat cushion comes with an easy-to-use manual air pump, so you can start training without other tools. Be careful when inflating. - Carefully insert the ball needle into the valve at an angle to avoid puncturing the bottom of the cushion. F. The ball seat cushion is made of PVC which is non-slip and wear-resistant and does not contain harmful phthalates. It is also relatively easy to maintain and clean.