If you look at the Mark Speedmasters as evolutions of the original moon watch, they increase in boldness, chunkiness, and variation from the original. The Mark IV has always been a Professional, the barrel-shaped case is real seventies design, something different.
Not for everyone but if you like the history of the Speedmaster and maybe a seventies fan then you combine history and fashion in your own way. The year 1973 is the year of introduction, the one you see here is from that year. It comes with service papers 2020 .
Feeling groovy or just looking for something unusual, maybe this Speedmaster is something for you.