Children's letter ring

Size method by age, birth date, hand size 10 cm, ring 3, from months to year, hand size if thin 11 cm, full 12 cm, ring 3, from age two, thin hand size 12 cm, if full 13 cm, ring 3, and if full ring 4, from age 3 years to 6 years, hand size.. thin 13 cm, full 14 cm, ring 4, from age 7 years to 10 years, hand thin 14 cm, full 15 cm, ring 5, from 10 years to 15 years, hand size if thin 14 cm, if full 15 or 16 cm, ring 6, and the best measurement is by meter, the correct measurement.