A is called the "lay flat" size and is one standard for labeling the size of a pole pocket....I've also seen them labeled based on the diameter of the pole i.e. if you have a 2" pole then your banner has a 2" pole pocket which in fact is a larger "lay flat" size than 2". I tend to use the lay flat size and just be familiar enough with the process to know what size pole is accommodated by what size lay flat. I also have slices of different sized pole pockets labeled and tacked to the wall for employees to use as reference...