Measure the size of your dog. Choose according to the corresponding size. If you have any questions, please contact the seller. If you do not measure the specific size, please do not buy. Size(CM) S: Bust 25-35CM Back length: 26CM M: Bust 34-40CM Back length: 30CM L: Bust 40-46CM Back length: 35CM XL: Bust 46-52CM Back length: 42CM 2XL: Bust 52-64CM Back length: 43CM 3XL: Bust 64-72CM Back length: 52CM 4XL: Bust 72-82CM Back length: 60CM 5XL: Bust 82-93CM Back length: 76CM Size(in) S: Bust 9.8-13.7in Back length: 10.2in M: Bust 13.7-15.7in Back length: 11.8in L: Bust 15.7-18.1in Back length: 13.7in XL: Bust 18.1-20.4in Back length: 16.5in 2XL: Bust 20.4-25.1in Back length: 16.9in 3XL: Bust 25.1-28.3in Back length: 20.4in 4XL: Bust 28.3-32.2in Back length: 23.6in 5XL: Bust 32.2-36.6in Back length: 29.9in Measurements may vary by 1-2cm. This is normal.