I got mine from Globetrotter long before
I have known CPF :-)).
It replaces the original tailcap from a 2AA (Mini M*g) light and adds two LED functions.
There is one red and one white LED. You can switch between the normal lamp assembly, the
white LED and the red LED. If you use one of the LED's it draws about 30mA current which
goes through the lamp assembly as well but is that low, that the it not lights up.
The LED's have got a fairly low output, therefore it is very suitable for reading (star-) Maps at night and preserving night vision.