This is a 2-inch nose adapter plate for STXL cameras.
This is a black-anodized, single piece of high quality aluminum, designed as an alternative to the 10018 standard dovetail adapter included with the camera.
It allows the STXL-6303, -16200, and -11002 camera and accessories to be inserted into a standard 2-inch draw tube.
Note that it may cause some vignetting with fast optical systems with the large 35mm full frame STXL-11002.
Now you can easily attach your camera to a refractor or Schmidt-Cassegrain telescope that may be limited to supporting a 2-inch nosepiece. This is common for most SCTs that are 12-inches and under, as well as most refractors under 150mm.
It is recommended that you have a high-quality focuser on the telescope, due to the weight of these series cameras.
Thanks to several customers for suggesting this adapter.
(The product image is a 3D CAD drawing. The actual product is black).