Ask any Arborist. Ask any oilfield worker. They will tell you how vital a diameter tape measure is to their jobs.
An Arborist needs to quickly determine the diameter of a tree, because he probably has to do this to another thousand trees. He uses this measurement to determine the amount of wood contained in the tree, so it can be sold for the wood content. For convenience and speed, he measures the diameter at the height of his chest. Diameter breast high (DBH) is the term used for this height. A tree diameter tape has a hook at the beginning, so the user can attach it to the bark, walk around the tree, and have the tape meet the zero mark. He reads the number on the tape, which is the diameter in inches.
An oilfield worker doesn’t need a hook on the end of his diameter tape measure.
He just cleans off the pipeline and wraps the tape around it. The answer is shown on the tape where it lines up to the zero mark. It’s important to him because he needs to know how much oil or gas the pipe can carry. Also, if a fitting needs replaced or modified, he needs to order the right size. Diameter tapes are a vital part of the oil and gas business.