Lets Go Pet Walker, Hands Free Bicycle Dog Leash for Medium / Large dog. 4 colors, Color Option: www.amazon.com/gp/product/B00937AX5S Easy install and quick release, no tool needed Safety- Dual spring/ single spring provide elasticity and avoid an unexpected pulling force while your dog meets your neighbors cat. A biker will not be controlled by the dog and Unhindered  Wont interrupt a bikers thigh COLOR OPTION: http://www.amazon.com/gp/product/B00937AX5S Fit for Small/ Medium / Large Size Dog Fit all kind of bike  Fit all size seat post 25.4-31.8mm Light weight  Only 350g*. All aluminum made. Aluminum 6061, various color: Blue and Red