The MC-520/MC-521 was designed to be easily held and intuitive to use. The thermometer has an oval cross-section and smooth lines for an easy grip in a wide range of hand sizes. Simply place the index finger along the inner curve of the unit and your thumb will naturally be in the correct position to press the measurement button. The tapering of the thermometer’s form from the measurement button to the tip of the probe improves visibility for correct positioning and more reliable, accurate measurements.