The SOPpr-1B-3-000 model is a mechanical single-hand stopwatch of the 3d accuracy class. It is designed to measure time intervals in minutes, seconds and fractions of a second. It is equipped with a 30-second sweep with the resolution of 0.1 s and a 15-minute register with the resolution of 1 min.
High measurement accuracy is ensured by a balance spring oscillation system that is usually used in pocket watches. A period of oscillation is 0.4 s. The stopwatch is started, stopped and reset by pressing the crown. The power reserve for a fully wound stopwatch is not less than 18 hours.