The size of the ring is also called "hand inch". Hand inches are expressed in millimeters and numbers. Hand No.5, diameter 13.7mm, circumference 43mm, hand No.6, diameter 14. 1mm, circumference 45mm, hand No.7, diameter14 mm, circumference 46mm, diameter14. The maximum hand inch has a circumference of 69.7mm and a diameter of 22.2mm, and is set to No.27 with ***27 digits. Precautions for wearing a ring to expand data 1. Everyone should pay attention to the fact that our fingers expand with heat and contract with cold every day, and they will change slightly with the change of seasons. When choosing a ring by hand, it should be worn slightly in summer and turned in winter, but it should not fall off. 2. When you feel that the ring is a little tight and you feel stuck in it, you should be alert. You can go to the jewelry store to modify the size. Don't be afraid to wear it reluctantly. We should be careful to nip in the bud! If you didn't pay attention to it at that time and didn't deal with it in time, you will regret it when the ring gets stuck in your hand! 3. Don't wear a ring when sleeping at night. People who sleep with a ring usually have mild edema after waking up in the morning. Although the swelling time is not long, if you don't take off your ring before going to bed at night, you will get stuck in the vein in the morning because your finger is swollen. Poor venous blood circulation will cause swelling, and the swollen ring will definitely get stuck on your finger, causing pain. When buying a ring, be sure to measure your finger size accurately. You can wrap your finger around it with a rope, then measure the circumference, and then find the number in the special wedding diamond ring table. But because our joints are slightly wider than our fingers, we can't wrap the rope too tightly, so we should leave room.