The Freestyler Paddle is a patented hand paddle designed to improve technique specifically for the freestyle stroke. Unlike previous generations of hand paddles, the Freestyler is not designed for resistance and strength training, but applies a hydrodynamic shape to decrease resistance through the water, thereby improving reach and distance per stroke.
The Freestyler's unique shape and 'skeg' design forces streamlined hand entry which lengthens each arm stroke. A longer stroke creates a better pull through, a better hip-rotation, and ultimately increases performance.
Great idea, but it doesn't work for me 
