Chrono Felix Pulso:
38.5mm with a step out bezel to 41mm
Pulsometer Mono-pusher
Press the pusher to start the chronograph and at the same time start counting your heart beats until you get to 30 beats. Then stop the chronograph and where it stops will tell you what your heart rate is. 
Can be used as a timer up to 30 minutes via the subdial at 3 o'clock.