There are many kinds of measurement methods for the ring mouth, mainly the following.
1, strip/thin line measurement method
When using strips or thin lines to measure the size, there may be some errors due to some irresistible factors, so it is best to measure several times to take the middle value; During the measurement process, do not pull the thin line too tight and not too loose.
2, internal diameter measurement method
3, ring size rod measurement method
A special tool for measuring finger size is called a ring size stick, which consists of a graduated size stick and a ring of different sizes. The usage is to wear the ring one by one, find the most comfortable ring to wear, and read the number of engravings on the ring rod.