Using the optical characteristics of normalized tissues between individuals to extract fixed fluorescence from the skin. This key step is to compensate for differences in absorption due to skin color (melanin content) and blood supply by measuring the reflection spectrum of excitation and emission wavelengths, plus the thickness of the epidermal layer and the differences in scattering of collagen tissue. Differences in the optical properties of these tissues between targets can overwhelm fluorescent signals of abnormal skin age. <br />1: Enter the age and gender <br />2: Place arm gently in the test slot. <br />3: Interpret results within 80 seconds. <br />4: Less than 50, normal. <br />5: 50-59.9, 2.8 times the risk of developing diabetes. <br />6: More than 60, 8 timesthe risk of developing diabetes <br />It went on sale in 2014 and has been discontinued.