The Challenger 15 D features a large uninhibited area that is perfect for swimming, exercise, and family fun. The Airless VIP Technology enhances the swim jet performance, and a variable speed system allows you to customize the pace. Plus, when it comes to hydrotherapy, rehabilitation, and relaxation, nothing compares to the Xtreme Therapy Seat and Xtreme Therapy Cove. The smallest footprint of any Challenger model, it’s ideal for small backyards.