This is a 3.5" Antec-style drive bay cover modified to provide two USB 3.0 and one USB 3.1 Type C front ports.
For the ports, I used: https://www.amazon.com/gp/product/B01KJPUI5W and
https://www.amazon.com/gp/product/B0755DDD9B connected to the relevant motherboard headers.
There are two STL files:
* antec_usb3.stl - file with all port/screw holes already made
* antec_usb3_solid_usbc.stl - this file has the USB Type C holes partially filled, and you will have to drill/cut them out after printing. This was done because of the fine detail of this area, which did not print will on my printer.