Size 1: Chest Girth: IN 8-10 or CM 20-25 and Weight up to 2 LBS Size 2: Chest Girth: IN 10-12 or CM 25-30 and Weight 2-4 LBS; Size 2.5 Girth: IN 11-13 or CM 27-32 and Weight 3-5 LBS
Size 3: Chest Girth: IN 12-14 or CM 30-35 and Weight 4 to 8 LBS; Size 3.5 Girth: IN 13-15 or CM 33-38 and Weight 7-9 LBS; Size 4: Chest Girth: IN 14-16 or CM 35-40 Weight 8- 12 LBS
Size 5: Chest Girth: IN 16-18 or CM 40-45 and Weight 12 to 18 LBS Size 6: Chest Girth: IN 18-22 or CM 45-56 and Weight 18 to 25 LBS Size 7: Chest Girth: IN 22-26 or CM 56-66 and Weight 25 to 45 LBS
Size 8: Chest Girth: IN 26-30 or CM 66-75 and Weight 45- 60 LBS; Size 9: Chest Girth: IN 30-36 or CM 75-92 and Weight 60-85 LBS; Size 10: Chest Girth: IN 36-42 or CM 89-107 and Weight 85-100 LBS