I received this 656 in trade this week. The watch is in great condition and is running well, about +4 seconds a day. I'm not sure if the crown is good, though. It screws down in less than one rotation. Is this correct, or does it need a new crown or tube? The bracelet also has folded ends. Did Sinn change to solid ends at some point? This one seems to be a relatively early model with the serial number less than 500. I'm also on the lookout for a Sinn strap tool to complete the boxed set if anyone has one to sell or trade. Thanks in advance to the folks who know these models well.