Depending on your system, you may need larger or smaller sizes to fit flow demands. Fitting connection size is typically expressed in dimensionless terms representing 1/16 of an inch. For instance, if someone calls out a “-0.6 thread,” they man the size is 3/8 or 6/16 of an inch. A “dash 32” size is a 2 inch connection or 32/16 of an inch. It is crucial to note that there are different connection sizes based on the thread type of the fitting you have.