The Valentino Extra was Campagnolo's boom era, entry level derailleur. Typically, it was found on 2nd from the bottom of the line, Italian bicycles. It's prime drawback was an overly stiff return spring which caused difficulty in executing smooth and accurate shifts onto larger cogs. The unit did tend to break-in a bit but I found that it did not hold its setting well. On the plus side, it was very robust. While it fared well compared to most of the entry level competition from the European manufacturers, I found it lacking compared to the entry level models from SunTour and Shimano, which were both strong and smooth.

Edit: Don't get me going on the push rod front derailleur, which was just about the worst front derailleur available at the time. The shifters are OK, and came with either a slotted screw or plastic wingnut to adjust the pressure on the stamped steel friction plate. The slotted screw was not very convenient, given that it was a fine line adjusting for relatively smooth shifts while maintaining enough friction to resist the return spring. The plastic wing nuts were too small and tended to break.