This is a mount for fastening the Satran Rotator on top of a standard 38mm diameter antenna mast pipe.
There is a hole on the side of the mount with a M5 screw that is used to fasten the mount to the top of the pipe.
It’s made from black 3D-printed PLA plastic and connects to the bottom of the Satran with 5 screws that are included. Mast pipe is not included in this product.
Source files for this component are available here, so it is also possible to print your own if you have access to a 3D-printer.