Beware! The one I bought, from the nice lutherloh person is utter garbage. The old ones are great. Often a sort of blued steel with brass at the hinges. New ones are aluminum and too tight to work. I was told you need to open them repeatedly to loosen the hinges up. Hundreds if not thousands of times, not good. When it is expanded they aren't even.
Find an old one. They cost about the same and they work