Size 1 measures 1.5 inches long, 1 inch wide, ¼ inch high, and weighs 1.08 oz. Size 1 is the smallest size, easiest to open, and ideal for children over 5 years old, and adults wearing light casual shoes. Size 2 measures 1.65 inches long, 0.9 inches wide, 9/32 inches high and weighs 1.08 oz. Size 2 is medium-sized, and ideal for most adults. Size 3 measures 1.8 inches long, 1 inch wide, 0.3 inch high, and weighs 1.58 oz. Size 3 is the largest size, has the most secure hold for active users, and is recommended for people weighing over 190 lbs.