LARGE SIZE-Designed for the maximum convenience and comfort for you and your pet while hiking, traveling, or taking your best friend to the vet, or going for a walk in the park. Measures approximately 11.4" x 12.6" x 16.8" (L x W x H),larger than most competitors in the market.Easily fits medium cats&dogs,even large sized cats and other medium pets. BETTER CONSTUCTION-Well ventilated design for optimal airflow, two-way entry for easy access, top mesh window for more headroom and visibility, and thick, soft fleece bedding for your pet resting and relaxing. This backpack is firmly structured, providing ample room for your pet to move around. ESCAPE PROOF- The last thing you want is an escaped pet running around the airplane cabin or outdoors. APOLLO WALKER pet backback carrier keeps your pet safe and secure while flying, walking, cycling, or hiking with claw-proof mesh and reinforced zippers. Carrier also has a leash tether to attach to your dog or cat’s collar if you decide to open the top window to let your pet stick their head out.