I am looking for the inside diameter. Someone is selling the thinner size, and they said it is 16cm (inter-length). I am not sure if that is the PM or GM size. I have very large wrists. The PM is too small for me.
I measured again, and it's definitely 5.9 cm across at the wided point. I know it's a GM because one of my receipts says so, and all three of mine are the same size. I tried the PM size, and it wasn't comfortable as I like mine to move.