Omega. A stainless steel tonneau-form automatic chronograph wristwatch, Ref. 378081/ST1780002, Speedmaster 125, circa 1974.
Movement: cal. 1041, automatic, 22 jewels, no. 35610024.
Dial: black, baton indexes, subsidiary dials for constant seconds combined with 24-hour indication and 12-hour register, secondary central hand for 60-minute recording, aperture for date.
Case: stainless steel, inner bezel calibrated for tachometer scale, screw-down back, stainless steel bracelet.
Signed: case, dial, movement and bracelet.
Dimensions: length 51mm, width 42mm.
Accessories: Service pouch. £1,500-£2,000

The Speedmaster 125 was the world’s first chronometer-certified automatic chronograph and was launched in 1973 to celebrate Omega’s 125th anniversary.