Posted September 17, 2022Updated September 17, 2022Outer diameter 2 inches. Non ID - ManifoldFYI. It says 2 inches in and out. That's an inside diameter of 2 inches. The tube has an inside diameter of 1 3/4. suitable for 2" OD pipe and not suitable for 2" pipe. To install, you need to expand the 2 inch ID.ProsVery Good ValueConsNot All Will FitΒ 0Β 0Β 0