An equal tee has all three openings of the same size, meaning the diameter of the branch outlet matches that of the run (main) pipe. This design ensures equal flow distribution in all directions.
an unequal tee has outlets of different sizes. One branch outlet is smaller than the other, while the remaining branch outlet matches the diameter of the run pipe. This allows for diverting flow from a larger pipe to a smaller one or vice versa, accommodating different flow rates or pipe sizes within the system.