It is this one.For the tubing you could use polycarbonate or borosilicate glass (McMaster-Carr) and use a couple of silicone O-rings in place of the metal compression ring.That's how my sight glass is constructed. I bought it from www.bargainfittings.com
Thanks. If you get around to it, can you post a pic?
Nice blurry pic here.
Edit: Another one. Still doesn't show you how it's constructed.