Note: We selling the rings for US size, so you will receive the ring in US size .( we will transform the Asian size you selected to the matching US size we have. ) Thank you. Perimeter of your finger: 57mm suitable for 16 Asian size; US size 7 57.5mm suitable for 17 Asian size; US size 8 58mm suitable for 18 Asian size; US size 8 59mm suitable for 19 Asian size; US size 9 61mm suitable for 20 Asian size; US size 9 62mm suitable for 21 Asian size; US size 10 63.5mm suitable for 22 Asian size; US size 10 64mm suitable for 23 Asian size; US size 10 66mm suitable for 24 Asian size; US size 11 67mm suitable for 25 Asian size; US size 12 1~2MM error is normal since the size is measured by hand. Thank you. How to measure the finger perimeter: Prepare a thin paper(or string) that width less than 1 cm, use the paper(or string) to round your finger that you used to wear rings. Make a mark at the junction,open the paper and measure the distance between the mark. That's the perimeter of your finger. Titanium steel is also called the 316L stainless steel.Its characteristics, resistance to strong acid, strong alkali, not change color, not allergic, rigid, deformation, brightness. No matter how the time is gone, titanium steel still exist for its unique apathy, will never change color . Titanium steel jewelry maintenance and cleaning is very easy, not in a strong acid, strong alkali environment, also do not need to deliberately maintain, simple and optional. When wearing the most important thing is to prevent the accessories by sharp objects scratch, and destroy the surface smoothness.