Hi 325addict,
The lamp in the link is one of many after-market lamp modules that follow what has become accepted as a "D26" or "26mm" or "P60" standard size.
The "3rd" party market of these from china come with all sorts of different "brand" names, but many of them appear to originate from the same few places. There are probably around a half dozen different variations of the "9V" style lamps available out there in what I would call the "cloud" of *ultrafire/superfire/trustfire/solarforce/G&P/spiderfire/romisen/etc etc etc", some are even sold as "7.4V" and stuff like that, most any of them will work fine in a C3/9P/G3 etc on either 3 CR123s or 2x17500 3.7V cells. You will also see 3.7V, 6V, and 12V versions of these lamps available for various other battery configurations. Considering they are only a few dollars from places like DX, I'd say they are worth a try at least, unless you must have mission critical reliability... in which case I would suggest an LED anyways
The link in the upper left hand part of my signature might help you get rolling on what batteries and bulbs are possible, the "G&P G90" is what most of these cheaper bulbs probably are, again, just sold under different names and stuff.
Also, check out LumensFactory for some decent after-market bulbs for SureFire flashlights. The LF bulbs are notorious for having maximum throw possible with very respectable beam quality, many folks who don't like the oval beams associated with SF stock lamps, have moved to LF lamps with good results.
Eric
