Module Number 4: An aircraft runway number for placing on the ends of a runway. Runway numbers designate the alignment of the runway in degrees from North. If the runway is used from the other end, the reciprocal number is used on that end.
There is a series of numbers used for such purposes, numbers 0 to 9 and letters L, C, and R. Place them as required. They are height adjustable, but the default height is suitable for my modular runway models. Airport Runway Module 16 Landing No Number is available without any runway numbers.