The Photon III is great; I have bought about two dozen of them, and given most away as gifts. Their big advantage is that you can use the lower power (dimmer) constant-on modes to conserve battery life. The short wavelength (white, blue, turquoise) Photons have only about 12 hours of battery life. This is extended roughly to 120 hours on the medium brightness, and 1200 hours on the low brightness. Yet, you can always override the low brightness mode by pressing on the front of the switch and get full brightness.
The blinking, or strobe modes (there are three fast, medium, and slow) are useful for marking things in low light conditions. My friends who bicycle at night have found the red and blue Photon III's good for this use.
The initial run of Photon III's had VERY stiff switches, so holding down the back of the switch (to change modes) was difficult. They are redesigning it with micro switches to take the place of metal contacts.
You can get Photon IIIs from Tim Flanagan:
northeastknives@bigfoot.com he doesn't have a website, but is a Forumite, and people, including me, have been very happy with his service.
Hope this helps, Walt
. just an all around neat toy, if you asked me
