There are 38 LEDs per "bulb" on the pro bar, so 114 LEDs total. The bars come with a light spectrum graph for the ruby pro gro bar, it weakly covers from 400nm to 600nm, and strongly covers wavelenghts from about 630 to 700nm, and also from like 710 or 720 to maybe 760nm. The strongest coverage corresponds with the "chlorophyll A red absorption peak", and the second strongest peak corresponds with the "far-red flowering and budding" area, while the third peak corresponds with the "chlorophyll B blue absorption peak", and is near the "chlorophyll A blue absorption peak". These blue spectrum peaks are around 460nm, while the red peaks are from like 630 to 760nm. All of these peaks are outside of the wavelengths that are visible by the human eye, and the grow bars really hardly give off any visible light, so they are probably giving off the right wavelenghts. I had an LED flashlight with one LED bulb and that thing was super bright, so the grow bars must be giving off a huge amount of light that just isn't visible.