The L4 reviewed here is the current revision which uses a SSC P4 instead of the original Luxeon V LED. The head of the L4 is made of three separate segments which are all adhered together. The bezel has some very shallow crenellations which allows light to shine through when placed head-down. A Borofloat glass lens sits at the front which is known for high thermal durability, although with LED sources it's not as crucial compared to Xenon or HID lamps. Behind the lens sits a aluminum reflector which has a light texture on it. Surface finish on the reflector is perfectly consistent from visual inspection. At the bottom of the reflector cup sits the LED which is just a hair off-center. Externally, the head features a similar design to most SureFire lights with a series of shallow scallops machined around the mid-section. These are more of an aesthetic touch and do not serve as an anti-roll feature. From the rear, non of the electronics are exposed. They are all encased in plastic which looks clean and well fitted together. A polished aluminum button serves as the contact for the battery's "+" end. There's also a raised plastic ring which serves as a reverse polarity protection in case batteries are accidentally inserted in reverse.

The battery tube is very slim and the L4 a very compact feel overall when held in hand. Most of the exterior surface has diamond textured knurling with three smooth faces where branding is printed. The knurling on the L4 is less aggressive than that of the L1 reviewed earlier, but still provides adequate grip. The Type 3 anodizing is well done with no blemishes and such, although there is some subtle tone variation between the battery tube and tail cap. A clip is attached towards the front end which slots into a small notch. It's held very secure and has good tension. There's also a small loop on the clip for lanyard attachments. The clip on my sample was noticeably bent to one side, but still usable. Threads at both ends of the battery tube are clean and well cut with no cross-threading or grinding issues. The threads are of the regular style and not square-cut like those on the L1. Thick o-rings sit behind the threads on both ends of the battery tube which provide good moisture seals. The tail cap has a clean and simple design, most of it's exterior is covered in knurling. The rubber switch cap has a checkered texture and protrudes out the tail end which means the L4 can't tail stand, on the other hand it also makes the switch easier to engage. The switch mechanism has average travel and resistance, this allows for momentary activation without accidentally fully engaging the switch. It also provides a good tactile feedback when engaged, producing a clear audible click. The switch can be locked-out to prevent accidental activation by slightly unscrewing the tail cap. Note that battery changes are done by unscrewing the head instead of the tail cap as the rear end of the battery tube is to narrow for the batteries to go through.

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

The L4 is a simple, straight forward, single-mode flashlight. The beam produced by this revision which uses a SSC P4 LED has a discernable mid-sized hotspot which smoothly tapers off into the spill beam area. This beam profile is quite different than that from the original L4 which had a flood-type beam profile. Thanks to the well finished reflector, the beam profile is totally smooth with no artifacts at all. The color tint on this review sample has a noticeable cool, violet hue. The official SureFire web site advertises the L4 of outputting 120 lumens, which is actually under-rated as tests showed a peak of 191 lumens. The runtime however, could have been better. As can be seen from the graph below, while regulation is maintained almost perfectly with 2x CR123 cells, it drops to below 50% short of 2 hours. Although not officially supported, you may also use a single 3.7V 17670 cell in the L4, but it will not be regulated and output will not be as bright.

The Good - Excellent construction and finishing with a lifetime warranty. Simple, single-output user interface. Very clean beam profile. Compact size for a 2x CR123 light.

The Bad - Below average runtime. Costs more than other lights with similar performance.

The Relative - Beam has a noticeably cool violet tint. Uses a forward push button switch. Isn't able to tail stand.

Head (front view).

Head (side view).

Head (rear view).

Battery tube (front view).

Head (side view).

Battery tube (rear view).

Tail cap (front view).

Tail cap (side view).

Tail cap (rear view).