Borrowed one from a friend for monochrome luminance imaging using a 6.5 mm back-focus ASI 1600 Pro Cooled camera and a 2” threaded IR cut filter, with a vintage Nikon 4.0 ED 300 mm AIS lens. Used the 11 mm spacer ring to achieve 46.5 mm back-focus for the Nikon lens! For aperture control I use the trick of placing a stack of step down rings in the thread on the front of the lens. Now that I’ve ordered a new ASI 2600 MM with 17.5 mm back-focus I’d really like to use a 36 mm ZWO 7 position filter wheel. Unfortunately there is now way to achieve the 46.5mm back focus with the 20 mm additional path front wheel filter wheel. Wish ZWO would make a version of the adapter with 9 mm thickness. I’m certain I’m not alone wanting that capability!

This product should include a mechanism to open the aperture. I have an older adapter, completely useless for the ZWO products, but it does have a convenient lever to control aperture.