The imperial scale used for threaded items is written either n-n or #n x n.
The dash and the x are interchangeable, yet the dash is generally preferred.
The measurements for diameter (the first number) are written as a fraction of an inch. However, for figures lower than a ¼ inch, a hash (#) and a representative whole number are used.
The second number is the threads per inch (TPI). Threads per inch is a measure similar to pitch, but instead of the length of a single thread it considers the amount of threads in an inch space.
The length of the threaded item will sometimes follow the UTS measurement.
