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.
Industrial piercing is referred to those kind of piercings in which two holes are connected with the help of a straight jewellery piece. However, the term generally refers to the double hole made on the upper part of the ear cartilage. One perforation is made close to head while the other is made a little lower on the cartilage.