It is too big for EF 70-300 F/4-5.6 is usm... And the margin to adjust is too small to fit my Lens. So I am thinking what I am going to do with it.
I left some bad feedback but I found out that this is for Canon EF Lens not EF... So I made mis-order... If you have a EF 70-300 L Lens, this ring might fit.