20 mm conduit 2 in back box out

There are two versions of the desighn one has a hole in the top or bottom for conecting to a uk switch or plug back box side rectangular hole. The other one only has the two 20mm holes for conduit.

Advanteges of the box bottom half V2 with hole is that it is desighned to print with no supports and it has a hole in the bottom to interface with a UK back box side hole this is to help with complex situations were you need to connect multiple conduits to one back box but dont have enough holes to do it nicelly.

Box V2 is just the box which is desighned for no supports and has holles for two 3mm screws threaded inserts are a long term plan but dont work yet

Lid with hole is essentially just a lid with the ability to connect it to the side hole of a back box its verry unlikly you will need it but you might.

Lid is just a compatible lid with two holes for the screws and nothing else.