It's small but it can be dangerous when you put your fingers inside. It's made of plastic and metal. Most often it's square or rectangular in Poland. It's got two holes.
Socket
It's made of metal. It's oblong and it isn't big. It's used for opening or closing the door.
door handle
It's made of metal and a bit of plastic. It's hot during winter and cold during summer. It can be empty or full of water
Radiator