After 40+ years of continued dog pack innovation, the K9 Pack introduces the same trusted fit-designed with and approved by a local, Golden, CO veterinarian. The 4-point adjustable chest harness, independently adjustable back harness, non-slip buckle system, mesh panels, and perforated EVA foam offer a custom, comfortable fit and added breathability. Large: best for dogs over 80 pounds with large girth chests. Medium: best for dogs 40–90 pounds with medium girth chests. Small: best for dogs 20–50 pounds with small girth chests.