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.
Generally speaking, though, the cost for an industrial piercing is likely to be lower in a more rural area than it would be in a bustling city. The reason is that property tends to cost more to rent or own in bigger cities, since shop space is in high demand, but available property is limited.