Please refer to the second details picture on the left side and choose size mainly accordging to BACK since it's a four-leg item. This fashion and lovely jean pet clothes make your pet look cute and fashionable, protect your pet in an AC room or cold weather, and protect them from mosquito's bites. Perfect for outdoor, take photos, Christmas and everyday wear . Take each measurement a bit loosely and if any of the measurements are 'between' two sizes, or your dog is still growing, larger size is recommended. Don't buy a particular size because that is what you always buy in a pet shop or online store, look at the size chart for CHEST and BODY and confirm the size before buy. Use the cold water and hand-wash, the items should be stored in dry and ventilated room environment and when it's not needed in a certain time .