• Greenough zoom optical system- displays crisp, stereoscopic images while having the ruggedness to handle harsh environments of the laboratory or machines. • Widefield eyepieces 10X/F.N. 20. • All models except cat. #598-728-02 have 12V/10W intensity controlled halogen transmitted illumination on bottom. • All models except cat. #598-725-14 have 4:1 zoom ratio, WD = 80 mm and a magnification range: 1X-4X. • Cat. #’s 598-728-04, 598-728-10 and 598-728-14 have 12V/15W intensity controlled halogen incident illumination on top. • Power: 110V.