BOSU Home Edition Balance Trainer 72-10850-2XPQ The Bosu (acronym for both sides up) is a double-sided device that uniquely combines a ball and a step. One side of the device is a kind of pneumatic dome that flexes with every exerciser's movement, while the other is a flat, rigid platform. Two recessed handles make it easy to easily flip the device from one side to the other. The platform's diameter is approximately 65 cm. Version for home use only. Tips on how to inflate your BOSU Place the pump tip firmly into the hole at the bottom and inflate the BOSU to a height of approximately 25 cm. Warranty period: 12 months