Here is another tool that helps you develop speed and power. The Workoutz Overspeed Slingshot Trainer is designed to enhance multidirectional quickness. You get adjustable speed harnesses that connect to a resistance cord, which stretches to max length to propel the user faster. You get two connection points in the front and back of the harness.
The Overspeed trainer comes with a 4/8ft cord which stretches up to 32 feet. Costs as low as $79.95 at this time.