Updated topic as this light is closer to the Ultrafire C5 and not C8)
This started out with a $ 2.50 dollar Ultrafire Mini-C5 from ebay. (The 703 model)
The host is nicely built for a sub-3 dollar light, it looks like a C8 style, but miniature in size, comes with a bright orange switch boot, a single AAA , single mode, plastic reflector, lens, plastic pill , tail clicky, and the usual eye-searing, migrain-blue tinted dim strawhat LED that is found in most of those $1 police lights found everywhere. also its looks and feels much better than the cheaper-looking 3w police lights with a better switch feel. ( and it tail stands )
a benefit here is that it comes apart easily, and has a unique locking ring ( the gold ring) that allows the body to adjust a little when i did the upgrade.
- My goal here was to give this little pocket light a better tint and more output, but not to the point of sacrificing more of the already short run times of usual single AAA lights have.
(Image #1)
In Stock form, the light carried a 0.28 amp load from a single Duracell Alkaline to the 3 or 4 lumen generic LED. I could have upgraded the driver to the 20-mode 7880 to give this light alot more output, but pulling 1 + amps from a AAA alkaline will give enough run time to take the trash out at night then its flat. in this light i left the stock single mode driver in.
- First i torn down the light to see what i had to work with, and as with any super-low budget light it has a generic LED on a PC board, in a plastic pill holding it and the driver.
(Image #2)
- After some inspection and measurements, i discovered the aluminum head has a recessed shoulder on the inside parameter approximately at the height where the original PC LED was located, and with a little sanding the edges of a 20mm Star with a Cree XB-D Cool White Emitter dropped right in on this ledge perfectly, contacting the aluminum head for a bit of heat transfer using thermal compound.
(Images #4 and #5)
- I left the original Driver in the plastic pill, as it sits roughly a millimeter below the 20mm Star. After sanding down the top and bottom of the plastic reflector, ( with trial & error of sanding to get the reflector to sit perfectly at the right height on the XB-D to for the best hotspot focus,
(Image #6)
-I then press-fitted the reflector and lens back in the head. ( as both are just a press fit from the factory)
(Image #7)
- During this build process, i took the empty parts out to the shop to do some work on the lathe.
First i cut down the gold anodized lock ring, and machined some tiny “cooling fin” grooves in it, and colored the groove lands with laquer paint, then re-sanded them to give the finish.
(Image #1 & #2 on Photo 2.)
- After machining the bezel area, i re-assembled the light.
(Image #3 #5 on Photo 2.)
I re-tested the tail cap amp draw, and got close the same draw as the stock emitter at around 0.29 amps, giving this mini C8 a couple hours run time, but with over twice the output and a better tint.
(Image #4 on Photo 2.)
Maybe i could have built a little throw monster from this light if i used a dedomed XP-G2 or XP-E2 & a 7880 Driver or a different 4.2 volt driver to run it on a 10440. ( i just might do that some day when im bored. 
- Bottom photo is the Mini C5 in photo # 3 along side a standard Ultrafire C8, along with Ceiling beam-shots to show the original LED profile/tint compared the upgrade with the Cool White Cree XB-D.
- Run time is being tested as this topic was posted on a generic AAA Alcaline starting off with 1.50 volts, and will update it later when i have the times/results.
