Seiko 6139-6022 chronograph, also known as the 'Doctors' watch, or the 'Pulsations' watch. Why the name 'doctor's' watch, or 'Pulsations'? That's because this watch was intended for people in the medical profession. You can measure the heart rate with it. How that works: The outer ring has a scale with the numbers 100 to 11 and the base 10 indicates how many heartbeats you have to count before the timer stops. To use it, feel the patient's heart rate, reset the chronograph, start the timer, count 10 heartbeats, and then stop the timer. The number the second hand on the outer ring points to is the patient's heart rate (in beats/minute)...brilliant. The case of this Seiko 6139-6022 is 40 mm wide (without crown), and the after market Seiko signed steel watch strap is 24.5 cm long.