You can usually find nose rings/posts at 20g or 18g .. remember the bigger the gauge number, the smaller the thickness of the post will be.
18 Gauge
For piercing, 18 gauge. that's the same gauge as a standard earring. There is also a 20 gauge which is a little smaller than an 18 gauge and rarely used for body piercing. There are smaller guage needles for medical use. 25 gauge is the smallest typically used in outpatient health care settings.
Did u mean monroe? If so i think its a 16 gage.
20g. But that's a regular ear piercing size. So you'll move up to 18g.
it depends on the gauge they pierce it with. Mines a 16g but if your planning on hiding it, its very difficult
Yes
The smallest gauge needle that I'm aware of is 22g. But no one will pierce you with anything less than 20g, and that's usually in the nose. But, the standard size piercing needle is around 16-12g, but you can make a request to be pierced at a larger gauge, if there's sufficient flesh for it to go through.
6mm is equal to a 2 gauge.
18 or 20 gauge
5 inch gauge is garden railway but 3.5 inch gauge is the smallest elevated gauge for a railway http://www.rideonrailways.co.uk/
yes
20 ga but some sites sell stuff that's 22ga. Most gunned piercings are 20ga or 18ga and needles are either 16ga or 14ga.