Tri-Tube is used for pipe fittings and pipe connectors. Also known as pipe tee or tee pipe fitting, tee connector, it is applied at the point where the main pipeline branches off.

Tri-union is a type of industrial pipe fitting with three openings: one inlet and two outlets, or two inlets and one outlet. It comes in T and Y shapes, with both equal and unequal diameter openings, and is used at the convergence points of three identical or different pipe lines. The primary function of the tri-union is to alter the direction of the fluid flow.