The tee is a pipe fitting and a pipe connecting piece. Also known as pipe fitting tee or tee fitting, 

stainless steel equal diameter tee, tee joint, used at the branch pipe of the main pipeline.

A tee is a chemical pipe fitting with three openings, that is, one inlet and two outlets; 

or two inlets and one outlet. Where three identical or different pipelines converge. [1] The main function of the tee is to change the direction of the fluid

The representation method is as follows: For an equal diameter tee, such as "T3" (3 inches = DN80) tee,

 it means an equal diameter tee with an outer diameter of 3 inches. For reducing tee, such as "T4 × 4 × 3.5" 

(4 inches = DN100, 3.5 inches = DN90), it means a reducing tee with a same diameter of four inches and a reduced diameter 

of 3.5 inches. The material is generally 10# 20# A3 Q235A 20g 20G 16Mn ASTM A234 ASTM A105 ASTM A403, etc., tee,

 the outer diameter range is 2.5″-60″ (2.5 inches = DN65, 60 inches = DN1500), wall thickness 3-60mm, From 26"-60" 

(26 inches = DN650, 60 inches = DN1500) for welding tee. Wall thickness 28-60mm. Pressure classes are Sch5s, Sch10s, 

Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160,