The Michael Phelps Signature D is a step up from the Force D as it is offers a much larger exercise and swimming zone. It is made for more than just stationary swimming, the MP Signature D combines the benefits of aquatic resistance training with hydrotherapy and relaxation. With specific design input from Michael Phelps himself, you can rest assured that the MP Signature D has been specifically designed to deliver the very best in swim spa jet current. The Wave XP Propulsion System allows you to select the swim resistance level to suit your skill or fitness but also allows you to select different workout patterns from recovery swims to challenging interval training. At full speed you can achieve an astonishing stationary swim pace of sub-75s per 100m.