Description Optical System 10X WF eyepiece 1X to 4X objective Continuous zoom control Zoom ratio: 1:4 Viewing Head Interpupillary adjustment of 52mm to 75mm Diopter Adjustment Focusing Coarse focus adjustment 40mm height adjustment range on focusing mechanism 70mm working distance Stand 58.4cm (23 in.) of 360° reach 43.1cm (17 in.) of vertical height adjustment Easily move between small and large size samples Focusing mechanism, with smooth ball-bearing rack-and-pinion Sturdy steel construction Counter balanced horizontal pole Illumination No illumination