Prior Scientific has released the most advanced microscope illumination product available - the Lumen 200 series fluorescence illumination systems. Developed to replace the complicated standard microscope HBO type mercury lamphouses, the Lumen 200 is specifically designed to illuminate fluorescently labeled specimens using a proprietary 200 Watt metal arc lamp with an impressive 2,000 hour life span. The light is coupled to the microscope via a two or optional three meter liquid light guide which ensures even illumination and eliminates the need for complex bulb alignment. The Lumen 200's innovative design removes the lamphouse from physical contact with the microscope which eliminates heat transfer and provides thermal stability to facilitate long term experiments. The DC power supply eliminates light flicker for further performance enhancement. The Lumen fluorescence illumination systems are available in two models, the standard Lumen 200 system and the Lumen 200Pro version. The Lumen 200Pro version shares the innovative features of the Lumen200, while adding an integral six position, 25 mm diameter high speed filter wheel and high speed variable aperture shutter for attenuation or shuttering of the light source.