I ordered two sizes on this vest because my dog was right on the edge of Medium and Large. Keep Doggie Safe recommended going up on the size and as it turned out that did fit the best. I think it is a tad big loose, but the next size down was a little snug. We kept the large in the orange color and it should really show up at night. It is a fairly small vest which is nice for our hot Phoenix summers. The green/yellow was really nice color too, but its going back because it is too small. It has a nice area for his "SERVICE DOG" badge. I was hoping Simon would quit shaking with this vest, but no such luck, they all make him itchy I think. FYI He is a miniature Australian Shepherd (about 20 pounds) and needed the large. He's short but stocky.

I really like this harness. It's easy to put on and comes in many colors. I ordered one for my other dog which is how I became a fan of this harness when I got my new dog, I immediately went to order one for him. It has a double safety because it has a velcro closure which makes it adjustable and then it has a snap in connector which holds it all together. Great value.

Exactly the harness I've been searching for for my small service dog. She's comfortable and I'm comfortable!

Runs big for being XXS.

The soft mesh harness works beautifully on our 45 pound yellow lab mix. The mesh is very pliable, but but highly durable and well-constructed. We purchase a large, and found it to be a good fit with the easy adjustments provided. When fitted correctly, it is not uncomfortably restrictive around the neck or under the "arms". It is easy to put on because we have had experience putting on other harnesses with the same configuration it. We recommend that the manufacturer include instructions for anyone who has not used this style of harness before. None came in our package.
The double metal loop leash attachment on the belt across the back gives extra security for our girl who tends to pull us along at times. We are very satisfied with this product,and will be purchasing a couple more in different colors.