18K yellow gold Omega Seamaster chronograph,Ref. BA.145.006-67, circa 1968, is a rare water-resistant, 18K yellow gold wristwatch with round button chronograph, registers and tachometer. The 38mm x 37mm case has a screw-down case back with logo, concave bezel, and straight lugs. The champagne two=tone gold dial features applied gold and black baton indexes, outer minute/seconds and 1/5th second divisions, outermost tachometer graduated to 700uph, subsidiary dials for the seconds, the 12-hour and the 30-minute registers and gold and black painted baton hands. The movement is calibre 321, 17 jewels.