Very sweet, vintage (circa 1970s) Tissot PR516 Chronograph. Three Register, Pulsations ("Doctor's") Chronograph powered by the workhorse Lemania Cal. 1281 Movement. The first 15 minutes of the outer bezel are graduated in Base 15 Pulsations; one starts the chrono, counts 15 pulses, and the seconds timer indicates beats per minute. The rest of the bezel is tachymetre. 100% original and in good condition overall.