Malleable iron. Flat banded. (In pricing, the run size is first and outlet second). Standard Malleable Iron Fittings, Fed. Spec. WW-P-521F, ANSI B-16.3 (Dimensions), ANSI B-2.1 (Pipe Threads), ASTM A-197 (Chemical & Physical Properties). On reducing size tees, the sizes are shown in A side, B side, and C middle sequence.