This item works great when used for an extension tube.
Very well made I have the older TV version and this is made so much better. The picture shows only one thumb screw but their our two. Also a brass ring for a better grip and a nice finish. The reason for 4.5 stars it is a bit pricey and the male end isn't grooved for a more secured connection. I gotten this for my TV 76 so all three powers on my Denkmeier binoviewer comes to focus.