The flow passage produced by our company is manufacured by special machines,which produce a range of sizes. 35-0.8-75-n38-1-75-nManifoldExplination of the Manifold,take 35-0.8-75-n as an example,35mm is the diameter of manifold,0.8mm is the thickness of manifold,75mm is the distance between two holes,n is the quantites of the holes. Solar Copper Flow Passage