The Seachanger Color Engine is an accessory designed for use on the ETC Source Four by the Ocean Optics company. The Seachanger uses four dichroic color filters to turn a standard Source Four into a CYM+G color mixing instrument, with millions of colors instantly available. The Source Four is unscrewed at the gate and the Seachanger is installed between the burner and lens tube assembly. The Source Four interchangeable barrel, Iris slot, gobo slot, and gel frame slots are all unaffected by the presence of the Seachanger. The Source Four is powered by the usual dimmer and an additional true non-dim circuit is required to to power the Seachanger (on board power supply). Provide DMX control and address it via the push buttons on the front. There is a stand alone mode for operation without DMX as well. Seachangers are an outstanding alternative to using color scrollers. Although they are priced higher than scrollers, they provide a larger range of colors, don't require a power supply, and you never have to replace a gel string so in the long run they will be cheaper. The Seachanger comes in the following designs: -Profile XG: Accepts ETC tubes. The dichroic filters in this model are designed to maximize pastel colors for typical theatrical use. -Wash: This unit replaces the standard ETC lens tube with it's own zoomable fresnel lens. -Studio Dichroics: introduced in 2008. This is a Profile fixture that accepts ETC lens tubes. However, it features more heavily saturated dichroic filters than the original XG. It is design for use in places like studios and dance clubs were stronger, richer, bolder colors are more desirable. -Nemo: New in 2009 a plasma source lighting instrument with dichroic filters. Uses ETC lens tubes. 15,000 lumens from a 180 Watt Plasma light source rated for 15,000 hours of use. Uses the same heavy saturated dichroic filters in the Studio Dichroic's model. Weather resistant. An excellent choice for clubs, out door displays, places that are difficult to access. Note: The Seachanger adds nearly a foot to the length of a Source Four. Because of this added length a standard factory yoke has extremely limited tilt range. Unless the instruments will always be hung at about a 90 degree angle, you should purchase a 16.5" extended yoke.