BOSU® PowerStax™ were made to elevate your BOSU® Balance Trainer by 10cm and your workout to another level! The PowerStax™ also give extra stability to your BOSU due to its wider base and the capability to add up to 15kg of water. In this way you can use it as a base to stabilize your BOSU (dome up or down) and an extra resistance/load for a more exciting workout!