!Warm Tips!:1. How to measure your dog?Using the tape measure, usually choosing the size by measuring in CHEST, BACK, and NECK, not weight or breeds merely.Give priority to measure CHEST, not too tight, and leave 2-3 finger's space for best fit & comfort. Please refer to the size chart clearly before shopping.2. Your pet usually wears size S doesn't mean all size S will fit him/her.Don't buy a particular size because of the different designs on a different shirt.Refer to the Size Chart on neck, chest, back confirm the size before you want to buy.3. If any of the measurements are between two sizes, choose the larger size.If your measurements are toward the upper end of the range given for a particular size,You may also need to choose the larger size.Important Size & Weight Attention:Weight Data is for a Reference, Please Actually Measure your pet's Neck, Chest, and Back Length for Choosing the Suitable Size.