A portable instrument which enables a person to measure his pulse rate, vital capacity and/or pulmonary peak flow during exercise comprising a single small, portable case containing all the elements necessary for taking such measurements, i.e., a mouthpiece into which the user exhales, a channel through...http://www.google.es/patents/US4679566?utm_source=gb-gplus-sharePatente US4679566 - Apparatus for measuring pulse rate, vital capacity and pulmonary peak flow
Apparatus for measuring pulse rate, vital capacity and pulmonary peak flow
