this is a very rare Omega De ville Prototype or schoolwatch from the late 1960s which we have received from our well known custumer and his outstanding vintage watchcollection. The condition of this 36mm chronograph and all of it´s parts is almost NOS. the movement-screws seem to have never been opened. The original vintage omega leatherband comes with an exceptional cool omega buckle. So what are the differences to the standart 145.017 we know? The first thing you would realize is the main handset with a longer minutehand and a longer lumepart. the original tritium in those hands (UV light tested) is matching the color of the tritium lumeplots on the flawless dial perfectly. Also the outer shape of those hands is exactly like the ones we know. It´s clear that those hands have always been in this watch, combined to that dial. There are two more points that proof it must have been a prototype or schoolwatch. No 1 is a missing serialnumber on the metal part of the movement where it would have to be normally (the screw had never been opened). No 2 is the correct caseback for that watch, not yet with omega engravings in the inside but saying „9-68“ instead, and „860 lemania“ on the outside. 1968 was the year the omega 860 was released. As far as we are aware of, the lemania 1872 was only called 860 when being produced for omega, so it´s very interesting that both words, „lemania“ and „860“ are engraved on the caseback at the same time, what would have been avoided for copyrightreasons in general. Another clear sign that this must be a watch that was only meant to be for internal usage. The movement is running perfectly in all functions with no service being needed. This is probably one of a kind in the Omega watchworld.