Abstract: A preferred form of a battery-powered, portable flashing superluminescent light-emitting diode safety warning light 10 is described having a single SLD 40 mounted at a shallow angle of between 3 and 22 degrees on a reflective printed circuit board 54. The SLD 40 has a narrow optical band width that is directed to a thin right angle lens 24 that is mounted in a curved condition between sidewalls 16 and 18. The lens 24 has a smooth outer surface 62 and a grooved inner surface 64. The inner surface 64 has parallel "V" shaped grooves formed therein that form linear prisms 76 that extend in a curved contour between the sidewalls 16 and 18. The light 10 has a battery-powered electrical circuit 50 for pulsing the SLD 40 at a frequency of between 1 and 3 Hz and with a pulse width of between 10 and 50 percent of the frequency period. The electrical circuit 50 utilizes a NPN transistor 98 that is mounted backwards for turning the SLD 40 OFF and ON during the duty cycle.