VINTAGE SEIKO TANK WATCH 4100-5009 ORIGINAL BOX 1976. COMES WITH ORIGINAL OUTER BOX, INNER MATCHING BOX, INSTRUCTIONSx TWO BOOKLETS. THE WATCH DATES TO JULY 1976- SERIAL NUMBER 670080. THE WATCH ITSELF IS IN VERY GOOD CONDITION , HOWEVER THE WATCH ONLY WORKS OCCASIONALLY. IT CAAN WORK FOR DAYS ON END AND KEEPING GOOD TIME THEN IF YOU TURN THE WAATCH UPSIDE DOWN IT STOPS. ANY QUESTIONS DO PLEASE ASK.