Prior's proprietary 2,000 hour life, 200 watt metal arc lamp, 2 or 2 meter liquid light guide provide unrivalled versatility & illumination power. The Lumen 200 utilizes a metal halide lamp. 2000 hours of stable output. Coupled to the microscope using a liquid light guide there is very little heat transfer helping to eliminate thermal drift during time lapse experiments. The Lumen 200 also incorporates a variable light attenuation control to reduce the potential of bleaching and phototoxicity. Remote mounting. Stabilized DC power supply. Quiet operation. Easy to view display screen for bulb life indication and alarm description. Knurled light guide clamping knob for secure light guide installation. Adapters available for all modern research microscopes. Six position adjustable aperture/intensity knob to protect samples from photobleaching. Easy bulb replacement.