Small Electronic Enclosure Design and Manufacture

I need to design and manufacture a small electric enclosure.

The sketch is attached

The enclosure has an external thread M20 with step 1mm

The enclosure has a translucent window, 5mm diameter

I need
- 3D model to be designed
- 20 parts to be manufactured. (Matt finish, should NOT look like a 3D print)
- 20 nuts to be purchased and screwed onto the part to ensure a proper fit
- 20 translucent windows inserted into the top hole

Thanks