Medical apparatus, namely, non-invasive, diagnostic units used to measure vascular function and diseases and states and physiological conditions involving the vasculature, namely, sphygmomanometers, oximeter, photoplethysmogram, electrocardiogram, mental health, stress, stress tolerance testing, phyiscal tolerance testing, non-invasive measurement of hormones and non-invasive of cardiac stress as well as brain waves (EEG); medical devices to detect and measure photoplethysmographic signals be...