The Lambda 721 is a new concept for combining up to 7 separate LED cubes with different spectra into a single common output beam. The LED cubes contain the LED, collimating optics, and a filter. These LED cubes are easily exchanged and installed with no tools required. Each LED cube is collimated before entering the optical path through the bandpass filter. The filters for each LED cube also function as mirrors that reflect the collimated beams from the previous light sources.