Measuring a bicycle chain's pitch can be used to identify chain wear and flag the need for a replacement chain and/or cogs and chainrings. Bicycle Chains: Length, Width, What's Best to Buy etc.
An industrial, or scaffold, piercing is made up of two holes that are connected by a single piece of jewelry (usually a long barbell). An industrial piercing is commonly made through the cartilage on the upper ear, with one hole close to the head and the other further down on the outer rim. Two or more industrials on one ear is sometimes referred to as an ear cage.
A. The starting gauge for industrial barbell piercings is typically 14g. If your piercer uses a 16g needle to make the holes for your industrial piercing, you can swap your starter jewelry out for a 14g barbell relatively easily once your piercings are healed. If you need to use a little lubrication to get the slightly larger barbell in, use a water-based lubricant like Astroglide.