The listing, HALLOWEEN: Jack-o-Lantern/Pumpkin ~ Dog Harness - new on display card - small has ended.
This measures about 6" from legpit to legpit. It's 4.5" long. The opened collar, with its insertion closure, measures about 12" when open. The wrap-around ribcage measurement, with its Velcro closure, is about 16-18" when open. The Velcro closure allows about a 2" adjustment. I would estimate that it would fit a dog weighing from 10-15 pounds. In other words, it's too big for a Yorkie (classified as XS) but would fit breeds such as Pekingese, Shih Tzu and similar breeds of average stature for their breed.