OMAX 20X-40X-80X Binocular Stereo Microscope Total Magnification: 20X, 40X, 80X; Viewing Head: 45 degrees Inclined 360 degrees rotatable binocular; Eyepiece: A pair of WF10X/20, a pair of WF20X Locked in; Objective: Rotational 2X and 4X Diopter Adustment: Diopter ring on left eyepiece tube; Interpupillary Distance: Adjustable 2-1/8inch ~ 3inch (54mm - 76mm) Working Distance: 3inch (75mm); Field of View: 1mm - 10mm; Focusing: Focusing knobs on both side Tool-free focusing knob tension adjustment Stage: White/black plastic stage plate 2-15/16inch (75mm) in diameter 5-year warranty against manufacturing defects