Help with Origin and maker

I’m stumped. Does anyone know the country for this piece? Its crossed keys in a square cartouche. It is in three pieces, held together with mounted screws and handmade nuts. looks handmade. makers " H N ". It looks like Tardy 110 [ Naumberg] or 45[Estonia] but I’m not sure. Anybody can help me?
hn keys sm pic.jpg