one can never have enough ring sizers
"Are you based in Australia or New Zealand? Simply provide your contact details and we will ship you a FREE ring sizer that will assist in determining your correct ring size. Please wear the ring sizer at different times during the day to ensure you are comfortable with the size. The ring should be snug, but still able to slide over the knuckle.
Please note: This ring sizer should only be used as a guide and/or as a validation of your ring size. It is best to be professionally measured at a local jeweller to confirm your ring size."