The Copyright of Design Act 1842 initiated the use of the diamond registration mark used to confirm that a design has been registered in Britain . The mark on this knocker is unfortunately illegible how ever it does allow us to date this knocker to 1842 or later. How much later? Good question. There are clues showing that this is an early device. The main clue is that the mounting bolts have been set into the knocker while it was still in its molten state, later examples would have screw in mounting studs. We are confident that this knocker is an early one and that it is at least 150 years old. In remarkable condition for its age, the knocker arm is cast as a fish like creature. Totally original, the mounting studs have been re threaded as the old ones were badly worn. Suitable for doors up to 5.5 cm thick, thicker doors will require a recess for the securing nut. Alternatively we are able to supply extension tubes, at cost, on request.