Go to Ofrei search for the inserts and it will give you the sizes, WSO sells parts that replace gen parts. If your bezel is a different size after you measure yours you will know which one to buy.
Ofrei state the 45mm bezel is Outside 40mm and Inside is 30.6mm. So does it means that the Outside is the whole bezel or just the insert itself? Thanks
The watch is 45mm. diameter of the bezel is a tad smaller at 43.40mm. (give or take)
This leave you a couple mil from the edge of the bezel to the edge of the insert.
My insert on my 45 PO is 40.31 outer and 32.42mm inner. Depends which version you have mine I don't think takes gen parts if your is newer it should.