Whether you're giving a lecture on the evening sky, or deconstructing pie charts in the boardroom, you will appreciate the power of the Zhumell Green Astronomical Laser. The 5mW laser diode produces a 532 nanometer green beam which is visible for up to 0.5 miles (0.8 km). Not to be confused with red lasers of the same power, this unit looks brighter because it falls in the region of the spectrum of the human eye's greatest sensitivity.