Simply Dog is a Sport pet brand which we bought for our little dogs to keep them warm. Because of the size of our dogs these sweaters were to big. These are really cute, they are green and orange with little fox ears. There is tags on the them to help with the best fit for your dog. Please measure around the dogs chest for girth measurement. There are some breeds that correlate with the sizes but those are just for reference. Just to give you reference one of my dogs is a yorkie very small around 3 lbs and the xs is to big.  So please measure for your best fit.