To ensure your safety, our ball chairs uses a specially designed 100% explosion-proof structure inner ball, which will make the inflation process a little more laborious than a normal exercise ball. When the inner ball is inflated to about 80% of its full size, you may have the false feeling that the ball can no longer be filled with more air. (Which it actually can.)

   Incomplete inflation can cause the inner ball to look small and not be properly seated on the base like you described. If this is your first time ever to inflate an exercise ball and you choose to use the included quick air pump, we strongly recommend flowing the two-step inflation method:

  1. Inflate the ball to 80% of its suggested diameter. Let the ball sit for 24 hours.
  2. Keep inflate the next day. Use the included Measuring String to determin

  Based on feedback from other customers, bike pump/tire inflator/air compressor can also significantly improve the first inflation experience.
 
  We have included a valve adapter with our latest batch and recommend trying it out as well. Don't worry about over-inflation, the size of the measuring rope calibration is the fully inflated size. It will take a lot more air than you actually believe it can.

  In order to ensure that users of different weights can obtain the best user experience, they have introduced a new technology in this product upgrade that can dynamically adjust the size of the inner ball.
  
  The solution is surprisingly simple. If the user's weight is not more than 100 kilograms and they find the inner ball posture unstable during use, please continue to inflate the inner ball to a diameter of 58cm. If the user's weight is over 100kg, it is recommended to inflate the inner ball directly to a diameter of 60cm (in this extreme case, the installation of the cover may be slightly difficult). Please rest assured that at these two diameters, the safety and service life of the inner ball are not affected.

  You must be an owner of Starfish Chair.

  Please note the box is marked by the sitting height of the entire starfish ball chair after completion of assembly. The 65cm size model you own is equipped with a 55cm diameter liner ball, it was not a packaging error.Please rest assured to inflate and use.