This is a Lockable Zoom Stereo 0.7-4.5X Simul-Focal Trinocular Microscope Head with a simultaneously-active photo port. Designed to outfit with a variety of lens accessories to increase or reduce magnification. Smooth in operation, it has a calibrated zoom range operable on both sides of the head. The trinocular model with digital camera is excellent for photo microscopy or LCD screen. View sharp, erect stereo images over a wide zoom range, with 45-degree inclined ocular tubes. Designed to fit 3" (76mm) collars, the head can be used with a huge range of support systems, including most of our column stands, and single- and double-arm boom stands. This model also provides a zoom lock to maintain a fixed magnification for calibrated measurement applications. This series is an ideal microscope for studying living organisms, dissecting small specimens, studying crystalline or rock structure, plus electronic and small part inspections.