Tees are pipe fittings and pipe connectors. 

Also known as pipe fitting tee or tee fitting, tee joint, used in the main pipe to branch pipe. 

Tee is a kind of chemical pipe fittings with three openings, that is, one inlet, two exits, or two inlets and two exits, with T-shaped and Y-shaped, equal diameter orifice and reducer orifice, which is used at the confluence of three same or different pipes. 

The main function of the tee is to change the direction of the fluid.