The head of the LD10 has a clean looking cylindrical design with a chunky hex-shaped at the neck which provides grip for twisting and also serves as an anti-roll feature. Up the front the head has a smooth bezel, behind which sits a toughened ultra-clear glass lens with AR coating. The reflector used is of smooth aluminum which is well-polished with no noticeable flaws. As with most lights with use the XP-G LED, it sits well-centered at the bottom of the reflector cup since the size and shape of its PCB allows the base of the reflector cup to align nicely with it. This reduces the occurrences of off-center LED's as was seen often with XR-E's.

The entire light is finished in black Type 3 anodizing with a smooth texture. Most of the battery tube is covered is textured knurling which should provide more than enough grip even for the greasiest hands. There are some flat faces machined with some branding printed on as well. New to the LD10 is a removable titanium-coated pocket clip which allows for the light to be carried head-down if you prefer it without the holster. Threads on both ends of the tube are cleanly machined and came well-lubricated too, very smooth with no grinding or cross-threading encountered. The threads at the rear end are anodized which allows the LD10 to be locked-out by slightly loosening the tail cap. Speaking of which, the tail cap is mostly covered in knurling too and has a partially raised lip which allows the light to tail stand while still providing comfortable activation of the switch. There are slits machined through both the raised lips which allows for lanyard attachments and such. The LD10 uses a reverse push button which means momentary activation won't be practical. The switching mechanism feels nice and secure providing an average amount of tension and travel, and produces a positive click when fully engaged.

If you're unfamiliar with any of the terms used in this review, click here for explanations on common flashlight related vocabulary.

The user interface of the LD10 is very similar to other Fenix products before it. There are two set of output modes depending on whether the head is loosened or tightened. Within these two sets are various output modes which are cycled through by half-pressing the tail switch.

Set 1 (loosened head)
Off > Low > Medium > High > S.O.S.

Set 2 (tightened head)
Off > Turbo > Strobe

Fenix advertises the LD10 R4 to output a maximum of 132 lumens, so I was really surprised that this particular review sample managed to push a peak of 176 lumens out the front. This is the highest light output reviewed so far coming from a single 1.2/1.5V AA light. On the other hand, it's also hard to tell whether this boost in output is actually from the premium R4 binned LED used since the driver used in this LD10 seems to be pushing the light much harder as can be seen from the shorter runtime as compared to say, the earlier L1D model. Luckily, regulation is still maintained well with NiMH cells. The beam profile produced has a narrow hotspot with a large, soft corona tapering towards the spill beam. Output color was noticeably cool. In terms of beam quality, the smooth reflector does a great job of focusing a clean beam to no apparently visible artifacts.

The Good - Very bright output on Turbo mode from a single AA powered light. Clean design with functional design features like its anti-roll neck, removable clip and raised lips on the tail cap. Maintains regulation well on all output levels.

The Bad - Slightly chunky, but otherwise nothing significant.

The Relative - Beam is clean and artifact-free with a noticeably cool color temperature. Utilizes a reverse push button switch. Is able to tail stand.