Specifications:
Medium-- Back Length: 32 cm / 12.59 inch, Chest Girth: 52 cm / 20.47 inch, Suggested Weight: within 16.53 LB
Large-- Back Length: 35 cm / 13.77 inch, Chest Girth: 58 cm / 22.83 inch, Suggested Weight: within 22.04 LB
X-Large-- Back Length: 37 cm / 14.56 inch, Chest Girth: 64 cm / 25.19 inch, Suggested Weight: within 27.55 LB
XX-Large-- Back Length: 40 cm / 15.74 inch, Chest Girth: 69 cm / 27.16 inch, Suggested Weight: within 33.06 LB

SIZE ATTENTION:
1.If any of the measurements are "between" two sizes, choose the larger size is recommended. If your measurements are toward the upper end of the range given for a particular size, you may also want to choose the larger size, as you may also wish to do for heavily coated dogs to accommodate all that fur.
2.Take each measurement a bit loosely, so there will be room for your dog to move and breathe, but not too loose.