The head of the LD20 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. The front half 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 LD20 is a removable titanium-coated pocket clip which allows for the light to be carried head-down if you prefer it without the holster. There's a subtle design difference between earlier LD20 models, this new one has has additional bands machined in at the rear end of the battery tube. This seems to me mainly cosmetic and doesn't add any functional characteristics. 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 LD20 to be locked-out by slightly loosening the tail cap. 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 LD20 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 LD20 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

Unlike the earlier LD10 R4 reviewed, the output from the LD20 R4 doesn't seem to have a drastic boost as compared to the earlier XR-E based LD20. On the contrary, output actually is noticeably less than earlier 2x AA models which seems weird. Regulation is maintained very nicely through all levels of output, though it drops rather quickly towards the end of the battery life. The beam profile produced has a narrow hotspot with a large, soft corona tapering towards the spill beam. In terms of beam quality, the smooth reflector does a great job of focusing a clean beam to no apparently visible artifacts. Beam color temperature is almost pure white, looking just slightly cooler then sunlight white.

The Good - Great build quality as expected by Fenix. Fit and finish are well done. Runtime and regulation are above average.

The Bad - Maximum output falls short compared to earlier models.

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