Emulate True Tungsten Dimming with LED – Repurpose, Revitalize, Reuse: The RETRO™. The RETRO-Classic™ is a 0-100% phase dimmable (forward and reverse) variable wattage LED 2700K-6500K 80-97 CRI engine. Designed for SCR, TRIAC, or IGBT dimmers. This light engine is a direct replacement of existing incandescent lamps in a wide range of applications.