They use the same 1.5" belly strap and almost 2" buckle in the x-small as they do in the x-large. As you can see from the photos, they cut into my small dogs armpits making it very uncomfortable to walk. They end up stopping and sitting down until I adjust it, but it just creeps back up. As others have said, the strap loosens which makes it hard to keep the harness in place once I move it down. But, here's the really bad part. I purchased from Joyride and they are charging me $7.95 shipping AND a restocking fee! Complete and total rip off for a product that has to fit to be functional.