Bought a large, it’s a little big for my small cat, and a little small for my large cat. It has a leash built into the inside of this, so if I put a harness on the small cat and hook her up she should be fine. The larger cat just flops over the top edge so it won’t work for him.
I'm really happy it came! My dog seems to like it! Medium is perfect for a chihauhau! The seller was definitely helpful and always messaged back! Took a month and four days to come to Arizona. Definitely recommend!