Body:They body of the LD10 is similar in size to most 1x AA cell lights. If you are used to carrying lights in holsters, the LD10 will be perfect on your belt as it comes with a holster too. Do take note that the holster also has a new design and is now a velcro flip-top style rather than the slip-in elastic style of the previous models. The entire light is coated in Type 3 anodizing which now has a more matte texture, this is much like the very first Fenix lights released such as the LDx series of lights. The body is cylindrical instead of hexagonal like the LD01. The front half of the battery tube is checkered while the rear half is smooth and slightly slimmer, probably for holding the light in a cigar grip. The head is smooth with a couple of ring designs around it. The aluminum body of the LD10 is very thick and sturdy and should hold up well. Inside the body is all nice and cleanly finished. The threads on this light are very well machined, they are very smooth and clean. Throughout the entire testing of this light, I did not experience any signs of cross-threading or grinding with the threads. Threads on the rear end are anodized so loosening the tail cap allows the light to be locked-out to prevent accidental activation. The tail cap houses a reverse push button. The rubber cap over the switch is smooth and doesn't have any texture on it. I really like the response of the switch, it's not too soft or too stiff and it has really short travel. This could be a bad characteristic if your carry this light in your pocket though since the switch is much easier to turn on. There's a thin band of checked texture around the tail cap which helps a little when unscrewing the tail cap. The LD10 now has raised lanyard slots machined on the tail cap which serve to allow the light to tail stand, and also makes it easier to activate the switch by thumb and also LD10 have the feature like every new version of fenix flashligh, body clip which is not too tigh and easy to use. The "-" contact spring is gold plated and all the rubber o-ring came very well lubricated.

Bezel/Head: The head houses an XP-G emitter and focused by a textured aluminum reflector. The LD10 uses a newly designed reflector, different from that used in the L1D model. Emitter and reflector are aligned very well, perhaps leaning just a hair to one side but really it's almost perfect. The reflector rests on the silver ring of the XP-G instead of around it on its PCB. The lens used is made or hardened AR coated glass for increased light transmission as compared to regular uncoated glass. Another new design to the LD-series of Fenix lights are that their bezels now have shallow crenellations which allow light to shine through when placed head-down. The Type 3 coating is a little smooth for my taste, which coupled with it's short battery tube, sometimes makes it slightly difficult to twist for single handed changing of operating modes. The exterior of the head now has a raised ring machined around the rear area which has four flat faces which serve as an anti-roll feature. The emitter module is sealed inside the head and is not easily disassembled.

Output: The LD10 has 4 outputs and 2 modes in total, separated into 2 sets according to the position of the bezel. Cycling through modes in either set is done by half-pressing the push button, sort of like how the auto focus works on a digital camera.

All the different levels on the LD10 are controlled by true constant current regulation. This means that you will not experience any high frequency effects of lower frequency PWM. The tint of my sample is of a neutral white and doesn't seem to lean much to either the cool or warm side. The beam profile produced by the new reflector is cleaner and focuses a slightly more intense hotspot. The dark ring-shaped area around the hot spot is much more subtle. As you can see from the control shots, the corona around the hot spot is skewed to one side. This is due to the misalignment of the die (yellow square area) within the LED package. This is the result of the manufacturing process of the XP-G LED produced by Cree, not Fenix.

Regulation is held very well with the LD10, regulation and performance are above average and comparable with the earlier L1D. Though the LD10 seems to be driving the LED just a little bit higher, with a trade of to runtime. The regulation is also tighter with the LD10. While with the L1D, the light output dims down to a much lower level when the batteries can no longer maintain regulation, the LD10 will totally go off.

Runtime Plot:

Batteries	Level	Runtime	Percentage
1 x AA 2500mAh	120 Lumens	1 hrs 30 mins	50 %
1 x AA 2500mAh	94 Lumensl	2 hrs 6 mins	50 %
1 x AA 2500mAh	47 Lumens	6 hrs 1 mins	50 %
1 x AA 2500mAh	9 Lumens	~ 34 hrs	50 %

Switch: The switch is a rubber covered clickie and is fully recessed in the tailcap which allows the light to stand on end and be used as an electric candle. Despite the fact that the switch is recessed, it is very easy to use. Click on, click off. You can lock-out the switch by unscrewing the tailcap 1/2 turn. This will prevent accidental activation when packing the light in your backpack or luggage.

Seals / Water Resistance: The lights are protected from the environment by an o-ring at both ends of the body tube, a rubber switch cover and a sealed bezel. Fenix advertises the light as "waterproof" with no specific depth rating. I would call it "dunkable" but not "diveable".

If either gets wet inside, just disassemble as much a possible without tools and let dry before using again.

Ergonomics: Nothing special to report here, except that both small and easy to carry. Obviously the LD10 is smaller and easier to pocket.

Batteries: For batteries, this light is approved by the manufacturer for use with AA alkaline, AA rechargeable NiMH cells, and AA L91 Lithium cells. All others are at your own risk. The input voltage for the Fenix LD10 head is 0.9V to 4.0V only.

To change out the batteries: unscrew the tailcap, drop out the old cells, place in new cells observing proper polarity. Reattach the tailcap and you're ready to go.

Accessories: Several accessories are included with the light. Inside the package you will find holster, spare O-rings, a spare rubber switch boot, a wrist lanyard, and a body clip. The Fenix brand is one of the few I have received that included this many accessories, and I have never seen a light include a spare rubber switch cover.

What I Liked: Waterproof, Tough/impact resistant, Good battery life, Bright, Easy battery change, Lightweight, Stands up

What I Didn't Like:Nothing, it is a pretty good product for home and travel used

Picky Little Things: Slight purplish tint to the beam in the samples received - yours may (and probably WILL) vary.

Conclusions: The Good - Very bright output on Turbo mode, great build quality as expected by Fenix. Fit and finish are well done. Runtime and regulation are above average.
The Bad - Nothing significant. The Relative - Beam has a neutral white color temperature. Uses a reverse push button. Is able to tail stand.

Quick Facts Table: