... -STEP Eye piece12.5×Total magnification Ratio10×, 16×, 25×(standard configuration)6×,10×, 16×, 25×,40×(professional configuration)Range of pupil distance55mm ... ~78mmField of view 40× (Ø5.5mm), 25× (Ø8.5mm), 16× (Ø13.5mm), 10×(Ø22mm), 6× (Ø34.7mm)Slit width0 ~14mm adjustableAdjustment ...