The Honer is a typical German derailleur from the 1950’s. It is extremely strongly constructed in well finished and lushly chromed steel. Every small component looks as though it has been machined to fine tolerances.
Despite all this love and attention, it is a single pulley, pull-chain design - meaning that capacity will be negligible and the gear change like stirring porridge with a tennis racquet. This design was already past its sell-by date in 1951.
You could just about get these derailleurs to work acceptably across three cogs mounted on a Torpedo three-speed hub-gear, but they were of no use for anything else. The hanger plate on this example, which fits inside the drop-out, indicates that this was exactly the intended purpose of this particular derailleur.
In the photograph I have disengaged the main spring to allow the gear to take up a more normal position.