Weather Beta, regular or the Joules Weather Beta, Rambo, or Dover Riders International. I have all of them for my dog, (she’s very spoiled!), my favorite so far is the Dover Riders Int, it is new and the velcro is really good. It is only 100g of insulation, but then if I want more warmth, I will layer one of the Weather Betas on top… The Rambo velcro died after like 2 winters…
I ordered the Dover Riders Int one online, and it says to measure from the base of the neck to the base of tail. So I did that, and Bailey measured 16". So I ordered a small, which measures 16.5". I got it, and it measured 19" across the top…which is what they call a medium. I went to my local dover, and was able to try on another small, same problem. We tried on an XS and it is a tiny bit small, but its fine. So moral of that story, the dover sizing is weird! Try it on if possible!