As it says is a 5-mode driver supplying arround 1A of current. It works fine from 3,7 to maximum stated voltage. It does not work properly with voltages lower than 3,7V. On flashlights with one LiIon cell it will dim as long as the battery voltage falls bellow 3,7V. The soldering quality is not I... As it says is a 5-mode driver supplying arround 1A of current. It works fine from 3,7 to maximum stated voltage. It does not work properly with voltages lower than 3,7V. On flashlights with one LiIon cell it will dim as long as the battery voltage falls bellow 3,7V. The soldering quality is not the best but I can live with this. Is good enough to make it work reliably. Personally I don't need the SOS mode at all. The strobeis of some usefulness if I use it as a front light on my bike, but I have another light fot this purpose. I bought this driver in order to use it in my flashlights that use one LiIon (18650) battery. It seems that is not the perfect choice for this use. I must use two CR123 type of cells in series if I expect it to work as described. It is not a bad circuit, it works fine if you use it with supplyes of 3,7 volts and above. Read more