1.5 inch rigid pipe and 1.5 inch flexible rigid pipe.
Best to use a plumbing cleaner then pipe cement to assemble. Pipework pushes inside this part.
This product is great for increasing the flow going to the end manifolds from the jet pump. Instead of a standard 90-degree tee being used to split the flow of water to the manifold this wye is an inline splitter that keeps the flow of water going in a straight line.