The Source Four and more The ubiquitous ETC Source Four has new models and features available. The Source Four 750 has all the features of the Source Four with more light output, through the use of a new HPL compact filament 750W lamp. The Source Four 750 also features a thermally insulated rear handle that allows for easier and safer instrument aiming and focusing.
Other enhancements to the Source Four series of ellipsoidals include an improved Source Four 19-degree model. A new lens