This black anodized ring adapter you lets you attach 78mm-connection accessories to your C11 telescope. A perfect connection - connects a new focuser to your Schmidt-Cassegrain C11 telescope. Now you will always be able to find the precise point of focus with your telescope.
The advantages in a nutshell
reduces from C11 thread to 78mm diameter
5x M4 Allen screws for connecting a focuser
adapter length 31mm