Several features of this early Edison lamp help to precisely date it. Prior to 1884 all Edison lamp bases incorporated a strain relief ring above the threads. In 1884 this design was changed and the ring was omitted from the short threaded base. Another key identifier is the heavy use of copper that forms the joint or “clamp” between the lamp’s carbonized bamboo filament and the leading in wires that carry the current to the lamp. By 1887 the copper electroplating method of clamping was changed to a carbon paste joint. The “EDISON’S PATENT” (no dates) label also signifies that this is an early example of an Edison lamp.