The Kurgo Auto Zip Line™ is the easiest and most convenient safety harness and restraint system for your dog. A nylon webbed line simply attaches between the rear seatbelts or rear passenger side handles, creating a tether run. This secure line allows the dog freedom to roam in the backseat of the car and allows the driver to focus on the road ahead thus reducing driver distraction. The Kurgo dog harness and leash integrate with the Zip Line allowing you to quickly transition from walking the dog to getting on the road. Small 10-25 lbs. Medium 25-50 lbs. Large 50-80 lbs. X-Large 80+ lbs.