The PCT is a versatile upgrade for compatible compound microscopes. It provides all of the tools necessary for use with phase contrast and brightfield. Phase contrast is used to reveal detail in indistinct objects, such as unstained cells and microorganisms that would otherwise appear invisible. By using a combination of specialized objective lenses and a modified light condenser, these invisible objects can be visualized by manipulating variations in phase. This contrast method provides far more detail than darkfield. The turret condenser not only provides the annuli needed for phase contrast, but also a brightfield setting with an iris diaphragm. This versatility makes life a lot easier by allowing you to switch between lighting methods by simply rotating a dial. Each annulus on the turret can be centered, and a telescopic centering eyepiece is also included for precise alignment, guaranteeing optimal results. For monochromatic viewing, a green filter is provided to limit light to the central portion of the spectrum. Four plan-achromatic objective lenses are included, each equipped with a phase ring. These provide sharp, high-contrast images at magnifications from 10X to 100X. Compatible models include: B340, T340, B400, T400, B450, T450, B460, B490, T490, B590, T590, B600, T600, B680, T680. The turret is designed for bottom-mount condenser holders. Because of its weight, a screwdriver is included to assist in tightening retention screws. Specifications Condenser Mount: Bottom mount Mounting Diameter: 37mm Model Compatibility: B340, T340, B400, T400, B450, T450, B460, B490, T490, B590, T590, B600, T600, B680, T680 Condenser Type: Turret design with phase contrast and brightfield Numerical Aperture: 1.25 Immersion Medium: oil Centerable Annuli: Yes Objective Lens Magnifications: 10X, 20X, 40X, 100X Objective Lens Optical System: Finite Objective Lens Mechanical Tube Length: 160mm Objective Lens Mounting Thread: RMS 20.32mm Objective Lens Parfocal Distance: 45mm Contents: One turret condenser Four objective lenses (10X, 20X, 40X, 100X) One centering telescope One green filter One screwdriver