On the blue one a common piece of black ****** on the bottom and a half coupling welded on the side. The white one was either a 1/4 coupling cut in half, or a reducing bushing works, some I have welded on a structural nut, bored and tapped, put 3/8 90 degree hose barbs on. There are probably a thousand ways to do it. Its nice to be able to see oil level with them running. I have never let one go to the point of the hose getting hard where its an issue, so easy to replace.