A
keychain-sized
flashlight that uses a hi-intensity
LED instead of a
bulb. It comes in many classic
LED colours, as well as a very cool
bluish-white colour, very similar to
HID headlights seen on
expensive cars.
The
design is very simple: Two coin-sized
lithium batteries stacked between the
leads of an LED housed in a
plastic case with a little
switch that
breaks the
contact between batteries and LED (
why didn't I think of that).
Because LEDs are very
efficient at converting
electricity to light, they are said to be able to light continually for about a week.