As a USB microscope,It Magnification: 30X (Fixed,at 10mm FOCUS and display on 17” screen by a 640X480 resolution).Focal distance: 5mm to 35mm in front of the opening of specula. if you only need microscope function,please see my other item about USB digital microscope.because the microscope Magnification only 30X(Fixed).It only good at observe the eardrum.If you have any question,please tell me before you bid.