Size SM: Top/under: Manufacturer's listed size: 29.1 - 31.5 inches (74 - 80 cm), 24.4 - 26.8 inches (
Size MD: Top/underneath (Manufacturer's size): 31.1 - 33.5 inches (79 - 85 cm), 26.4 - 28.7 inches
Size LG: Top/Underneath (Manufacturer's size): 33.1 - 35.4 inches (84 - 90 cm), 28.3 - 30.7