Quite simple yet relatively nice looking slide-in case for CH340E USB to TTL converter.
Case sized at about 29*24*12 mm, designed with 0.2 mm tolerance in mind. CH340E PCB is 16*18 mm. 
Recommended to print in transparent or semitransparent material to see LED indicators better.
I used transparent PETG with silver colored glitter (aka metal colored filament) with 0.6 nozzle. The side with the hole oriented towards bed. The connector was originally straight so I just bent it to be angled one.
To assemble the device first slide USB socket of the PCB in the corresponding hole of the inner case. Push it in to make it flush with the case. Then slide the outer case on.
Pay attention to the orientation! If you set the bottom of PCB to be lower side, the hole of the inner case will also be in the lower side but the hole of the outer part will be on the upper side.