The first thing I want to say about gauge as a unit of measure is that, like just about all non-metric units of measure, it’s shit. It means something slightly different in different industries. For example, if we look at hypodermic needles, there are various conversion charts online that all pretty much agree. This Wikipedia chart is probably a pretty good source. But then you run across crap like this chart for jewelry, and it doesn’t match up in the slightest. Then you have body jewelry and piercing charts that also don’t match up to the previous two. Here’s what each one says the millimeter diameters are for 10g …
Wikipedia Birmingham Gauge Chart (10g = 3.404mm)
Jewelry Site Gauge Chart (10g = 2.588mm)
Body Piercing Needle Gauge Chart (10g = 2.4mm)
Those are some pretty wild swings there… so like I said… the “gauge” unit of measure is shit and we should all be using metric values to communicate needle diameter.
The outer diameter of the xG3 and all our other 3mm glass implants is approximately 3.75mm which is 9 gauge on the Birmingham Gauge chart.
The NExT and our other 2.1mm glass x-series implants use a needle with an outer diameter of 2.6mm, which is between 12g and 13g according to that same Birmingham Gauge chart.
The 4G needles we recommend using to make the incision and subdermal pocketing for Flex device installations have an outer diameter of 5.1mm.