Is Pet Designer Dog Apparel - Byrne Vest - Color: Yellow, Size: S For sizing chart, click on the other images link above. We recommend one size up for comfort if your dog's measurement is the higher end of the range listed. IS Pet's sizing tends to be a bit smaller. Please note that these lengths represent the size of the dog and do not reflect the actual length of the garment. 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. Sleeveless coat made of windbreaker fabric Fashion meets warmth for the great outdoor Comes in Blue, Pink and Yellow