... Microscope5.3×,8×,12×Diameter of FieldF38mm,F25mm,F17mmAdjustable Diopter±7DAdjustable Range of Pupil Distance50mm~80mmIllumination Source12V/100W,medical cold reflection halogen lamp ... (12.5X eyepiece). Big Objective LensDiameter of Field(mm)f250mmφ47.5, φ31, φ21f300mmφ57, φ38, φ25f350mmφ67, φ44, φ30f400mmφ76 Operation microscope