GI tee is a pipe fitting, typically T-shaped, made from galvanized iron (GI) that connects three sections of pipe, usually at a 90-degree angle, to branch or combine fluid or gas flow in plumbing and industrial systems. The "GI" stands for Galvanized Iron, a material coated in zinc for added corrosion resistance and durability. These fittings are used to split a single pipeline into two or join two pipes into one, forming a T-shaped connection point.