Omega has produced the Speedmaster Professional reference.145.012 from 1967 to 1968 (several models were delivered in 1969). Given its date of manufacture, it is known as pre-Moon Speedmaster. Actually, astronaut Michael Collins has released Speedmaster Pro ref.145.012 was used during the Apollo 11 mission.
Speedmaster Professiona, on the other hand, was first introduced in 1968 to replace 145.012 and was produced until 1981. In 1981, 145.022 was converted to 145.0022 reference (but kept the same case number) and remained in the catalogue until 1988. 145.022 is the longest – running Speedy Pro reference date. A year after the lunar-landing in 1969, there only have a few pre-Moon Speedmaster ref. 145.022 models.
As a result of a cooperation between Omega and Lemania, Calibre 321 manually calibrating its chain uses a column wheel chronograph system with a horizontal clutch. Compared to the cam-controlled chronograph, the pillar-wheel chronograph is considered to be of better quality and smoother operation – but more complex and expensive. The delicate design and sturdy movement are important to the history of omega replica watches, a brand beloved by omega lovers, and the brand recently announced that Calibre 321 will be reintroduced into production. 
Calibre 861, a subsequent manual winding movement (also based on Lemania) uses a chronograph to make the movement easier and cheaper. To be sure, replica omega expects the demand for the newly created “lunar replica watch” to be huge, so the chronograph made for speedo will need to be made faster. However, Calibre 861 has also led to a higher frequency. Its speed is 21,600 times an hour, compared with 18,000 BPH for Calibre 321.
In the current vintage market, Speedmaster Professional 145.012 is usually much more expensive than Speedmaster Professional 145.022 – about twice as expensive. That’s not surprising, since the early model was in production for only two years, and it’s the last Speedy of the coveted Calibre 321.
Speedmaster Professional 145.022 is still the affordable choice for the old Speedy, currently priced from $3,500 to $5,500. It’s been in production for a long time, so there are a lot of examples on the second-hand market right now. But as we have mentioned, overall demand for the old Speedmasters is on the rise. We wouldn’t be surprised if the price of speed bar pro 145.022 continues to rise if demand picks up. So, while they are still somewhat abundant today, examples in good shape may start to dry up.