not all led lights are 405nm. some companies use the higher 405nm wavelength because it looks brighter and tricks the consumer into thinking he's getting a powerful uv light. the higher wavelengths are also cheaper to buy. most of the rubrail leds are higher wavelength because the clowns that leave them on all the time want everybody to see them. the better led lights are 390-400nm. anything below 400nm won't hurt the fishing unless you turn it off and on. any light source turned off and on scares the fish. next time you're in a school of minnows, flash your light on and off and watch their reacton.