Want to run faster? Overspeed & Resistance Training with the Speedster Lightning Cord will help you develop longer strides, faster overall speed and more power. Go with the training bungee that pro coaches and athletes trust to take them to the next level - the Speedster Lightning Cord. Belts & Harnesses sold separately. Speedster Lightning Cords are made in the USA and feature Safety Sleeve Technology for ultimate injury prevention. Every Lightning Cord stretches 4x's its originally length, good luck finding that kind of stretch in another bungee.