The Bosu (an acronym for "both sides up") is a double-sided device that combines a ball and a step in a unique way. One side of the device is a type of inflatable dome that works with every exercise, while the other side is a flat and rigid platform. Two handles hidden in the recesses make it easy to flip the device from one side to the other.

The diameter of the platform is approximately 65 cm. The Bosu functions as a simulator of movements characteristic of various sports, with a primary focus on balance training. It is suitable for both static and dynamic exercises, as well as exercises that improve body balance. It also has a significant impact on core stabilization.

Exercises can be performed on one, two, or more devices simultaneously, including stepping up, stepping down, jumping, and squatting, with a variety of rhythms and positions.

• Inflate the Bosu to a height of approximately 25 cm.
• Carefully insert the end of the pump into the hole at the bottom.