Cartier. An 18K Tank Americaine automatic calendar wristwatch: the curved, rectangular dial with black Roman numerals, date aperture at 6 'o' clock, secret signature at 10 'o' clock and blued steel sword hands, the case back numbered 8172984 00400 and secured by eight screws, case approximately 23mm wide (excluding crown) x 40.5mm long and on black 'Cartier' strap with signed buckle/clasp together with fitted box, booklet and international guarantee.