The M28Z is ideal for laboratory, industrial and educational use. This stereo microscope features zoom objectives with a continuous magnification range of 10X to 40X, offering added versatility that is not an option with fixed power stereo microscopes. MAGNIFICATION 1X to 4X continuous zoom OPTICAL SYSTEM Paired widefield eyepieces are 45° inclined, with diopter adjustment. Interpupillary adjustment from 55mm to 75mm. Interlocked eyepiece tubes with diopter for increased focus acuity. Viewing head rotates 360°, locks in place by tightening thumb screw. Paired objectives are parfocalled, parcentered, and achromatic. Magnification changed by rotating magnification dial. ILLUMINATION 3W LED illumination provides bright, white light with virtually no heat. Top light adjusts for optimal lighting angles. Variable transbase illumination allows user to control brightness. Easy-to-replace LED illumination is energy-efficient and rarely requires bulb replacement. Dual illumination switches allow for 3 light settings. FOCUSING Rack and pinion focusing with slip clutch and tension adjustment. "Slip-clutch" system prevents users from damaging the focusing mechanism.