Afternoon all This is a beautiful example of the first electronic chronograph chronometer ever made and at the time Omega flagship chronograph. I wouldn’t think it needs much introduction to Omega enthusiasts but just incase; The Omega Speedmaster 'Speedsonic' was introduced in the early 1970's as Omegas flagship chronograph, considerably more expensive than the moon watch or other Omega chronographs and the only one (other than the limited edition Speedy 125) that was Chronometer certified. The Speedsonic was an adaptation of Omegas mosaba movement or as we know it the F300, a mechanical movement which ran on a battery and was controlled by tuning forks which vibrated at a frequency of 300Hz The movement was made under licence by Bulova, the chronograph version then adapted with basically and extra 'layer' for the chronograph operation. The movement in this watch was known as the Mosaba meaning 'montre sans balancier' translates for 'watch with no balance' In 1975 a new Speedsonic was £190 compared to £124 for the moon watch so it sat at the very top of Omegas Chronograph range and the price tag really did reflect the build quality of these watches, at 1/3rd more expensive than a moon watch they needed to be something special…………. They are! So good was the quality that in 1978 Omega send approximately 12 of this model were sent to NASA with Radial Dials (and Star made cases) to test them as a possible replacement for the famous 145.022 moon watch, they passed all of the rigorous NASA tests (I am fortunate to also own one of these watches #12) They were produced in small numbers (due to cost of the movements) and when new was one of the most expensive Omega chronographs in the range in its day it was amongst the most advanced Omega made, even by today’s standards it is a work of genius and becoming increasingly hard to find in good condition. This example is good cosmetically , the case nice and original some age related marks and links (worst detailed above) but these would easily refinish and the watch is fully functioning and working correctly including the date and day (notoriously an issue). Condition: Case: Originalcondition, some age relating marking and a few drinks but nothing that detracts. Case-back: Completely original and superb with only the lightest of marks Bracelet: Correct new ribbed rally band Dial and hands: Perfect and a lovely honey patina to both dial and hands. Crystal: Original crystal (a few light marks which I will polish out before shipping) Box and papers: Original papers and instructions, also supplied with Omega service pouch I am looking for a bargain £950 posted RMSD or International signed for Cheers Tom