The Pet Life 'Waggler Hobbler' Large-Pocketed compartmental animated Dog Harness Backpack features an expressive Penguin-faced animation that's both fun and functional. The Waggler Hobbler backpack features a large spacious zippered usable back pocket that is perfect for placing belongings. Exo-shell is composed of durable Nylon that is reversed with comfortable Micro-mesh for complete breathability and comfortability that gently hugs the body. The back of the harness features a harness ring and dual buckles connected to durable seat belt-like heavy duty adjustable nylon straps. Available in Multiple Sizes. SIZING MEASUREMENTS: (In Inches) SMALL: Length: 5.51" Chest Girth: 14.9 - 17.3" (Smaller sized breeds) MEDIUM: Length: 7.08" Chest Girth: 18.1 - 22" (Small to Medium sized breeds)