The new pro model is better than ever! Improvements made to the Professional model: 1.) A new axle was added allowing the footplate to rotate making operation smoother and more natural. Not only is the new design more durable. The reduced resistance allows the user to jump higher and farther. 2.) New nylon strap replaces plastic strap 3.) More durable rubber stopper that's easier and cheaper to replace. 4.) New light weight aluminum alloy footplate replaces the plastic footplate. This new plate is much stronger and lighter by 400 grams. Jump six feet in the airalmost effortlessly! Run with nine feet strideswith ease! Run at over twenty miles perhour! Powerizers have curved springs attached to the base, so when you press your feet downwards, the pressure of your weight creates gravitational energy. These super-charged springs push back to harness this energy, giving you the ability to jump to incredible heights and run with huge strides at amazing speeds. With a pair of Powerizers on your feet you'll be able to move like a superhero. The soar in adrenaline you feel when a small jump takes you high in the air above the tress is impossible to describe - it has to be felt to be believed. Running at greatly increased speeds will prove quite an experience too. Notice: Powerizers are safe to use, however mttext and Powerizer Ent. cannot be held liable for any injury resulting from the use of this product. You are advised to wear protective gear when you use your Powerizer and you should also be in good health to use them. Use with caution and under proper supervision.