1970 OMEGA Speedmaster Mark II (Ref. 145.014) CAL. 861 "Pulsations"

Following the Omega Speedmaster Professional that was worn on the Moon in 1969, Omega decided to come up with a watch that fit the design trends of the 1970s, thus the Omega Speedmaster Professional MKII was born. The Speedmaster Mark II came with the same Lemania based movement as the original Speedmaster Professional "Moonwatch", reference 145.022. This watch contains Omega’s original caliber 861 movement and was in production from 1968 and lasted until 1996 when Omega introduced the caliber 1861 movement. Unlike the Speedmaster Professional, the Omega Speedmaster Mark II has a barrel-shaped case that has polished chamfers and a brushed top and sides, giving it a different look from the standard Speedmaster Professional case worn by NASA Astronauts. The classic timing scale that the Speedmaster is known for is also different; it is under the mineral glass crystal and not externally located on the outside of the crystal as an external bezel, in essence, protecting the timing scale from scratches or disruption. Unlike modern timepieces with scratch-resistant sapphire crystals, pieces of this era were assembled with mineral glass crystals. 

In some very limited examples, Omega used different timing scales other than the Speedmaster's famed tachymetre timing scale. Their specialized bezels included the decimal bezel, the telemeter bezel, and the pulsometer bezel, which we see here. The pulsometer or "Pulsations" bezel was designed with medical professionals in mind to measure the heart rate. When measuring heart rate, it's designed for the chronograph to be started at the first heartbeat and stopped on the 15th. The second hand will then indicate the heartbeats per minute.