I use the QS8 connectors for distribution of 12V on my van for inverters and chargers. The connector by itself is hard to pull apart especially with cold hands and pulling on the wire isnt good practice.

The plug connector has a little shelf around the top of the connector making it easy to locate however the socket connector does not so to retain it in the chassis connector or the free plug you need to tap out the holes and fit a M4 or M5 grub screw. It only has to be tight enough to lightly grip the body of the connector. Dont drive it all the way in or you could short out the contacts!!

The body of the connector isn't a strain relief but more an oversized body which is eay to grip. The body is held on with M3 screws and a nut pushed into the connector part. I have left the top of the body closed and you need to use your CAD software to clear the path of the cable you are using.

Printed in PETG and it helps to print the chassis connector at an angle so the layer lines go through the print at an angle which makes it a bit stronger, but you will require supports.