Breitling. An unusual stainless steel manual wind chronograph wristwatch Referee, Ref 34-31, Circa 1973Breitling. An unusual stainless steel manual wind chronograph wristwatchModel: RefereeReference: 34-31Date: Circa 1973Movement: 17-jewel Valjoux Cal.7731 manual windDial: Black, luminous dot hour markers with Arabic 12 and 3, white outer minute divisions with 5 minute markers, red outer scale for 45 minute recording, subsidiary dial at 9 for seconds, aperture at 6 for showing full circle and small circle start-stop and return to zero function of the chronograph, white pointed baton hands with luminous inserts, cubist centre chronograph handCase: Brushed and polished tonneau form, snap on back, bi-directional calibrated bezel, crown flanked by twin chronograph pushers, No.1411075Strap/Bracelet: Black Breitling leatherBuckle/Clasp: Associated steel buckleSigned: Case, dial & movementSize: 40mmThis unusual chronograph was designed to be used by football referees with a scale for timing the 45-minute halves included on the dial. The reference 34-31 also features the 'Slow Chronograph' complication, when activating the chronograph the only visible action is in the aperture at 6. When the chronograph is running, there will be a large circle of lume; when paused, the display will show a small circle of lume; and when inactive, the aperture is empty.