S: Chest 24-28cm Neck 20-24cm (under 1.5kg), M: Chest 28-32cm Neck 24-28cm (1.5kg-3kg), L: Chest 32-36cm Neck 28-30cm (3-4.5kg), XL: Chest 40-46cm Neck 34-38cm (5-7kg), 2XL: Chest 46-59cm Neck 36-42cm (7.5-10kg), 3XL: Chest 59-65cm Neck 49-56cm (10-17.5kg)
Small (27.6 x 59.1 in), Medium (27.6 x 70.9 in), Large (27.6 x 82.7 in)