The Oslo Norway Elektrisk Bureau (EB) keys were very nice keys.

I understand that they came with both red and black insignia, this one is a red insignia which I've heard is rarer.

They had one annoying feature! If you didn't take the cover off just right the cover would crack.

The cover needed to be lifted by holding it by opposite corners (NW and SE or NE and SW) and gently lifting. Great key, any of you ever use one?