Maybe you mean pulse oximetry. It is the measurement of oxygen in your blood. It is measured when they put that clip on the tip of your finger.
Cant say from experience with this particular model whether it is an air or fuel screw, however; If there is only one screw then it does both. If there are 2 others near it then one does the air, the other two do the fuel. The factory standard setting for the main idle-adjustment screw on most bikes is 1 and 1half turns out from closed position. This is often the case with the other adjuster screws as well, but the mixture will need to be altered as the engine wears.