LETS GO Pet Walker for medium/ large Dog Leash Attachment for Bicycle. 4 colors, Gold, Purple, Blue, Red. Color may vary. Light Weight: Made of aluminum alloy for light weight and antirust for outdoor usage. (* only 350g for the model small / middle size dog), various color: Red or Blue Convenient: Easy to install, quick to release. (Less than 5 sec.) Safety: Even the dog run in different directions with bicycle, our patent design, Pet Walk, could effectively protect the rider's safety and Perfect for rider: It won't interrupt your thigh while you are biking. Fit for Medium / Large Size Dog Economic: Fit all kinds of bikes and all sizes of seat posts: MTB, road bikes, city bikes, full suspension, etc.