Project · ref 100027
Seiko 6139-6022 "Pulsation"
Seiko · 6139-6022 · 1971-11
About this model
A doctor's watch. The inner bezel is a Base 10 pulsometer: start the chronograph, count ten heartbeats, stop it, and read the pulse straight off the scale. The Pulsations references were aimed at medical staff in the early 1970s, and the scale is considerably more useful day to day than the tachymeter most chronographs carry.
Not been through yet
I have not had this one on the bench, so there is nothing written down. Ask and I will take a proper look and tell you what I find before you decide anything.