This watch is a sample for salesman which shows the engraved number on the watches back: M. 284 (M. = Muster = Sample). The crown on the back looks different to those beeing used later. The serial number is very low (00000422). The watch could be an example of a pre-series as also the lot number of the installed bar quarz is a lower number (013) than those of the most Junghans 666.02 with the number 122.