Very simple torch. Free and no adverts. Why did I develop it? Because others are either non-free or contain adverts and require Internet access. I don't trust them :)
Illumination should be simple: no design frills, no stroboscope, no audio and no other capitalistic fancies. And the most important - for free. Like the Ilyich Lamp was.
Tags: light, torch, lantern.
Correctly handle situation when the phone doesn't allow turn the flash on.