The method of expression is as follows: For an equal diameter tee, for example, "T3" (3 inches =DN80), the three means an equal diameter tee with an outer diameter of 3 inches. For reducing tees, for example, "T4 x 4 x 3.5" (4 inches =DN100,3.5 inches =DN90) means a reducing tee with a diameter of 4 inches and a diameter of 3.5 inches. The material is generally 10# 20# A3 Q235A 20g 20G 16Mn ASTM A234 ASTM A105 ASTM A403, etc., three way, the outer diameter range is 2.5 "-60" (2.5 inches =DN65,60 inches =DN1500), the wall thickness is 3-60mm, From 26 "to 60" (26 "=DN650, 60" =DN1500) for welded tees. Wall thickness 28-60mm. The pressure levels are Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS.