I love the style and quality of the K9 Sport Sack. Love the thick comfortable straps and the grey and leather style. The medium size fit my Frenchie perfect (His measurements are 16 inches length from neck to butt and 23 inches chest/girth). I get sooo many compliments, looks, and laughs as I ride around on my bike with him on my back :) He loves it too and is happy to step in the backpack, and the zipper makes it real easy to get him in and out. Also great customer service!