EURO connector lid for MIG welding machine

Today, MIG welding is done with a torch that's connected to the welding machine with a hose & connector known as 'EURO'. This lets you replace/detach the torch/hose assembly for transportation or - if the welding machine is multipurpose - convenience.
The EURO connector offers gas, wire and control signals all-in-one to the MIG torch & hose you connect to it.
But with the torch/hose removed, the connector exposes its internals to dust and dirt ingress, and my OCD does not like that. So, annoyed that no cover/lid for my new multiprocess-welding-machine's EURO connector existed, I made one myself.

To go with the torch/hose, a matching cover for that is available at https://www.thingiverse.com/thing:6621285