Most common sizes is 14 Ga or 12 Ga for nipple piercing. You will have less problem finding the jewelry for your nipples if pierced with 14 gauge. Please be aware that price is given only for one nipple ring/shield. So if you want to same nipple rings you need to buy 2. The reason is that a lot of people pierce only one nipple and we do not want charge them for second ring if they have no use for it.
How nipple rings are measured:
click to enlarge
