Alfie Couture Designer Pet Apparel - Frank Sailor Jumper - Color Navy Please note that this listing is for size XL. Best fit Neck girth: 15", Breast girth: 20", and Body Length: 14.25" Sizing for each dog is unique. Similar to our clothing and accessory, medium size from one designer is not the same for another. For example our 9-pound yorkie model usually fits either one of three sizes (i.e. XS, S, M) depending on the designer. We highly recommend you measure your pet precisely with a flexible tape measure to ensure the best fit. Contact us if you have question. We are happy to help. 0 0 0