This is a key holder that looks like a EU Schuko power strip. Use the plug as a keychain und simply plug it into the power strip. It can be attached to the wall with two screws or nails.
The tolerances are very tight so it is maybe hard to plug it in in the beginning. But that gets better over the time.
The power strip and plug are not real size so real plugs won't fit!
For me it worked best laying the plug on its side and using some support for the connector pins. I also tried to print it with the two connector pins facing upwards. But due to the small area touching the buildplate it won't stick to it well and you need good cooling to print it that way.