B021 Kids. B021A Adults. Hardwearing non-slip sole. Durable neoprene upper & heel toggle for easy fitting. Kids sizes: BB (5-6), B (7-8), I (9-11), J (11-12), K (13-2). Adult sizes: 2XS (3-4), XS (5-6),S (7-8), M (9-10), L (10-12),XL (12-13).