We bought these booties in size XL for our two year old, 86 lb. Golden Retriever, which is a perfect fit. He drags his back feet a bit on our faster paced long walks, which wears his nails down to the quick and causes bleeding, so we wanted a bootie to protect his paws. I was worried he wouldn’t tolerate wearing the booties, and I was also worried they wouldn’t be durable enough to withstand our 3 mile walks 2-3 times a week without getting worn down very quickly. I had nothing to be concerned about! He adapted to them right away- hardly any fuss at first and now he isn’t phased at all when we put them on. The booties are so easy to get on and off, and they are very light weight and breathable. After many miles in these booties, there is literally no sign of them wearing down! Highly recommend these booties!