The new redesigned Roadie harness is specially designed from the drawing board up to be a Canine Vehicle Restraint System. It is not a converted harness. Evaluated by experts and independently tested, Ruff Rider�s Roadie canine vehicle safety and training harness keeps the dog you love safe and secure while riding, braking or turning and affords the best protection in extreme situations. It easily attaches to any vehicle�s seatbelt system and includes a built-in short walking lead for all-around use. Every Ruff Rider Roadie is veterinarian approved and exceeds SAE tensile strength standards for human seatbelts. The Roadie canine vehicle restraint allows your dog to sit stand or lie down safely. Roadie is not designed to fit skin-tight like other harnesses and it should have several inches of play in order to be comfortable and function properly. The size SM1 fits dogs with a chest size from 19 to 23 inches which is measured behind the front legs and a maximum neck size of 19 inches which is measured at the base of the neck.