Well they are tapers I'm not sure what gage the smallest part is. They go up to a 0g. They are heavy and ment to stretch your ears out so even if you only get them part way on the weight will stretch the ear out .
Yes it fits in my 00 because it's a larger hole. But the largest part witch is the middle is a size 0g. So if your ears are smaller then that it would take time to get the hole stretched for a snug fit. Or if you have a size 0g. Now you could use this so slowly stretch the holes bigger .