Supply
Cost: Under $50
These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.
Watch or Clock with Second Hand
Cost: Under $50
These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.
Summary
A watch with second hand is easier than digital to follow when calculating heart rate, pulse and respiratory rate.
You might purchase this supply through one of these sources:
Drug Store