The bag is very well made, handy and spacious ,I have a 13 pounds chinese crested and I bought the large so she'd be more comfy (we have extra room for her toys and a blanket, but she could have fit in a medium). The large is verry big, not for a small framed person to carry on the shoulders, but  for myself 5"9 and my husband,it's purrfect. Gisele (our doggie) loves when we roll her around and wags her tail when she sees the bag ; she loves it even more now that she can tag along when we take public transportation :)