Blood oxygen saturation levels, that is. The Oxycheck device does it in a painless and fast manner, measuring your blood oxygen saturation levels and heart pulse rate in an instant without resorting to invasive measures. All you need to do is place your finger underneath the Oxycheck, press the “On” button and wait for a few seconds for the reading to appear on its LCD display. Apparently larger versions of this device are already in use throughout thousands of hospitals, so why not save yourself money in the long run by picking this up for $139.95? Choose from black or white colors.