Product description: Size 8 (inner diameter 1.8 cm), suitable for 5.7 cm finger circumference Size 9 (inner diameter 1.9 cm), suitable for 6 cm finger circumference Size 10 (inner diameter 2 cm), suitable for 6.3 cm finger circumference Size 11 (2.1 cm inner diameter), suitable for 6.6 cm finger circumference.