ST 378.0801 PulsRef

Introduced in 1973 for Omega's 125th anniversary, the Speedmaster 125 uses caliber 1041, a chronometer-certified version of caliber 1040, making it the first automatic chronograph to receive COSC certification. It is said that no more than 2000 pieces were made; although not immediately apparent from the specifications, the case is rather massive. The 'bar' bracelet, similar to that on the later Seamaster 'Albatros', measures 26mm at the case and tapers to 15.5mm at the clasp, and this version has the rarer pulsometer scale printed under the crystal.