This is a great winter jacket for puppy. I purchased the 4XL in Nov 2020 when my german shepherd cross puppy was 5 months old and approx. 40 lbs. Puppy measurements were 25 inch back length x 24 inch chest x 16 inch neck. Perfect length. It was a tiny bit big around the chest but she has since grown into it through December. Customer service was super helpful in providing guidance in ordering size.