Size Chart(In inches):
S: Chest: 16,'' Back Length: 11.8," Suggest Weight: 5.5-11 lbs
M: Chest: 19.7,'' Back Length: 12.2," Suggest Weight: 12-21 lbs
L: Chest: 23.6,'' Back Length: 13.8," Suggest Weight: 22-30 lbs
XL: Chest: 25.6,'' Back Length: 16.5," Suggest Weight: 31-36 lbs