The Consciousness is Fluid collection ring comes in three different sizes (circumference in millimeter)
S : 49.5 mm (US5)
M : 56.5 mm (US7.5)
L : 62.8 mm (US10)
How to measure your finger’s circumference
Take a piece string or a strip of paper, wrap it around your finger and mark the two ends where it crosses. Place the string or paper against a ruler. This is the circumference of your finger which you will then need to convert into millimetres.