Hi Danting, our ring sizes on our online store are universal so if you fit a size M then you should be fine with our rings too, if you are unsure then your ring sizer should be with you within a few days to confirm. We do not have a store for you to collect from, we are solely an online store, if you order the ring between sizes J - Q, you can return to us for a full refund or exchange within 30 days or of course send back for re-sizing if required.