Generic T-4 Equal-tube T-piece (T) push-in pneumatic fitting, 4 mm tube on all three ports. Used for branch tap-offs on instrument-air lines. Direct interchange with Festo QST / SMC KQ2T / Camozzi 6440 on 4 mm tube. Used in pneumatic control and actuation lines feeding cylinders, valves and industrial automation cells at 4-10 bar working pressure.