This is an OLD light. One of the first moving yoke lights in the entertainment industry. When they first came out they were only available for hire, and came with a Vari-Lite technician to maintain them. It's main features are super high resolution pan and tilt due to the use of geared motors with optical encoders, a massive optical path the full width of the light and a dichroic glass colour mixing system that takes up the whole length of the body.
These lights were available as tungsten and discharge lamp versions, with the dimming and discharge ballasts mounted remotely, making the lights quite compact and light.
There is a newer version of these lights, but on some jobs the older units are just better suited due to their high resilience to brief encounters with extreme weather.
The colour changing system uses small linear actuators to push four rings that surround the whole light and make the internal "fans" of dichroic glass rotate to either end-on or side-on to the light path, or any position in-between. The colours are Cyan, Yellow, Magenta and either a frost for diffusion in the tungsten version, or a black-out shutter in the discharge version.
Dichroic filters are basically a piece of glass with metallisation deposited on it to a very specific thickness matching a wavelength of light. They pass the desired wavelength and reflect the unwanted ones. This gives a slightly psychedelic effect as a red filter will appear as red glass, but as a green mirror.
These units require a local "repeater" unit to power their circuitry and pre-process/convert the lighting data. Up to six can be run from one repeater. Although used on DMX these days, they are capable of using a proprietary communication protocol that can send target positions and speeds that allow the lights to operate at much higher positional resolutions than a standard DMX stream offers, and move linearly from one position to the next.
Definitely a classic. These lights are all veterans of showbiz history.