Certina Biostar mechanical hand wound watch

Very rare 1970s mechanical Certina Biostar watch. This watch is the only watch that has a biorhythm complication in it. This particular one is 35 mm (wears bigger due to the larger dial,) it has an 18 mm lug width and it’s in near mint conditions. Everything is original except for the watch band. Runs and keeps perfect time. This model was featured on Hodinkee talking watches: https://www.hodinkee.com/articles/talking-watches-with-bill-higgins also, here is a website that goes a little more in depth about the Certina Biostar: https://www.vintagecertinas.ch/en/certina-biostar