This an upgraded version of the T660, adding a darkfield light-condenser for professional biological applications including darkfield observation. It uses an ergonomic design for comfort and a fluid workflow, and its achromatic optics provide sharp, color-correct images. The halogen illumination system provides low-fatigue, evenly-distributed light for maximum contrast and definition. This model is a popular choice for veterinarians and university laboratories. Specialized darkfield optics allow you to observe live cells including blood and other fluids, making it a great choice for clinics and medical labs. The trinocular head accommodates viewing through eyepieces and through the top-mounted photo port. The binocular viewing tubes use Siedentopf adjustment to easily fit any user. The head has a top-mounted, height-adjustable 23mm photo port for mounting optional cameras. C-mount cameras can be paired with various reduction lenses for mounting to the port and optimizing field-of-view. The objective turret provides instant access to 4 magnification levels to easily focus in on minute details from 40X to 1000X. This covers magnifications needed for studying hair follicles, cells, and bacteria. The turrets reversed orientation provides more working room above the stage. These high-quality lenses are achromatically corrected to improve resolution and color accuracy. The large 2-layer mechanical stage provides smooth and precise movement for examination of specimen slides. The stages low-position controls are conveniently placed near the coaxial focus knobs for a streamlined workflow. Examining specimen slides is intuitive and precise for users at any skill level. Built on Koehler illumination principals, the sub-stage lighting provides evenly-distributed light for optimal contrast. The halogen light-source provides bright illumination with a lower color-temperature for decreased fatigue when used for long periods. The Abbe light condenser has a high 1.25 numerical aperture for oil-immersion, and an iris diaphragm to optimize contrast and depth-of-field. The condenser holder uses rack-and-pinion height adjustment for precision control, and is centerable for proper alignment. The illuminators field lens provides an iris diaphragm to control light-spread, optimizing contrast and definition in specimen features. An oil darkfield condenseris included for darkfield observation using high-power objective lenses. The condenser is designed for use with immersion oil, and can accommodate higher numerical-aperture lenses. Darkfield observation will provide contrast in otherwise indistinguishable objects by highlighting changes in refractive index. This is particularly useful for observing live cells including blood analysis. Specifications Optical System Finite-conjugate Mechanical Tube Length 160mm Head Trinocular, 30A° incline, 360A° rotatable Interpupillary Adjustment Siedentopf compensation-free gemel, 55-75mm Ocular Diameter 30mm Ocular Diopters left ocular Eyepieces 10X Photo Port height-adjustable 23mm tube Objective Lenses DIN standard Objective Parfocal Distance 45mm Objective Mounting Thread RMS 20.32mm Objective Turret Reverse quadruple, ball-bearing movement Focusing System Coaxial coarse and fine focus, tension control Division of Fine Focus 0.002mm Stage Design Double-layer with caliper Stage Dimensions 180mm x 150mm X-Y Translation Range 75mm x 50mm Transmitted Illumination 12V/20W halogen Condenser NA1.25 Abbe condenser with iris diaphragm NA1.25-1.36 oil darkfield condenser Sub-stage Condenser-holder rack and pinion Power 85-230VAC 50/60Hz wide-band Objective Lenses Magnification Corrections NA Immersion Medium Cover-glass Thickness 4X achromatic 0.10 a? 0.17mm 10X achromatic 0.25 a? 0.17mm 40X achromatic 0.65 a? 0.17mm 100X achromatic 1.25 oil 0.17mm Packing List: One trinocular head One microscope body Four objective lenses: 4X, 10X, 40X, 100X One pair 10X eyepieces One oil darkfield condenser Three color filters One spare halogen bulb One spare fuse One power cord (US and Canada standard) One dust cover One sample immersion oil