ETC Source Four Ellipsoidal with a 10 Degree Lens Tube. There’s only one Source Four — the fixture that changed the lighting industry. Source Four combines the energy-saving power of the patented HPL lamp, with a dichroic reflector and optical-quality lenses, for the coolest beam on the market. That means your gels, patterns and shutters last longer and your performance space stays cooler. Source Four fixtures are supplied with a C-clamp, a color frame, and a slot for either a drop-in iris or motorized pattern device. Three-foot, three-wire Teflon leads with bare ends encased in black fiberglass tubing are shipped as standard. Source Four fixture bodies ship with C-clamp and standard bare-end leads.