Photon Freedom Micro
The photon freedom micro is the top of the line keychain light from LRI; the original creators of this kind of keychain lights. The freedom evolves from the photon microlight II and III combining all the features of the photon III in a single button interface.
The interface works as follows: from off you can turn the light on pressing the button and it will turn on on maximum brightness, you can then press the button and keep it pressed to dim the light. From off you might also turn the light by keeping the button pressed, then the light turns on in minimum mode and you can then press the button and keep it pressed to make it brighter. Once you reach maximum or minimum brighness mode keeping the button pressed you enter the flashing, strobe and SOS modes. From off you might also press the button several times quickly to access a signaling or momentary on mode, in this mode the light is off but every time the button is pushed the led flashes useful for morse if you know morse for example.
The freedom is available in different color cases: black, red, blue, camo, purple and you can choose several different led colors for the light: white, red, purple, blue, green, yellow, organge, turquoise, UV or IR. The lights are powered by one or two C2032 coin cells, they are of course shockproof and splashproof.
The freedom is probably the ultimate keychain flashlight, it offers multiple brightness levels, several useful modes and a nice interface taking almost no space from your keychain. They retail for about $20 and you can read more information in LRI's Photon Freedom official website.