"6139" is the Seiko movement that distinguished itself for being among the first automatic chronographs in the world, with a vertical graft. The use of the Seiko "Pogue" was an accident, as NASA couldn't supply all of its astronauts with the Speedmaster Omega, and so Pogue used his Seiko, appreciating it because of its suitability to zero gravity. Because of this, it is still remembered today with this name. Reference: 6139-6002 Period: 1970s Mechanical, hand-wound movement manufactured by Seiko, calibre 6139 with hours, minutes, seconds, chronograph, and day/date features The oversized case is 100% steel with a two-tone Pepsi bezel with tachymeter scale Knurled crown; short, curved lugs Dimensions: 41 mm excluding crown, 47 mm at the lugs Mineral crystal Screw-down case-back Gold dial with dark bezel (The internal bezel is fixed at 12 o'clock, but does not rotate as it does not work.) Steel 22-cm bracelet Seiko aftermarket bezel and hands The buyer is responsible for any customs duties. Water resistance is not guaranteed. The chronograph resets regularly to 12 o'clock Ships in an elegant case