S- 3-6M (Chest 16inch all around when laid flat and unstretche, stretches 3inches each way, Length 14inch)
M- 6-12M (Chest 18inch all around when laid flat and unstretche, stretches 3inches each way, Length 15inch)
L - 12-24M (Chest 20inch all around when laid flat and unstretche, stretches 3inches each way, Length 16inch)