The Preon series are the first from 4Sevens which run on AAA batteries. They are very compact and slender, able to easily into pockets and such. The entire light is coated in Type 2 anodizing and has a fine matte textured finish. Up the front the Preon I has a smooth bezel, sitting behind which is an AR-coated Sapphire lens which provides improved light transmission over regular glass. The reflector has a medium textured finish and well-polished with no noticeable flaws on its surface. The LED sitting at the bottom of the reflector is aligned well too. On the exterior, the head is a plain cylindrical shape with no additional deign touches or knurling. Since the Preon I is a twist activated light, you might face difficulty with greasy hands. Generally though, it works just fine under normal conditions.

As with the head, the battery tube is also a plain cylindrical design, apart from a slightly raised lip towards the tail end. The threads between the head and battery tube mate well with no cross-threading or grinding experienced during tests. A rubber o-ring sits just behind the threads on the tube end which serves as a moisture seal. In addition, the tail end of the battery tube can be unscrewed which allows for swapping out of the pocket clip which comes pre-installed. A lanyard attachment ring can be put in its placed, or removed altogether if you do not need either of these attachments. The Preon I is able to tail stand without problems on its flat tail end.

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

The Preon I provides a total of 7 modes of output. From off position, switching it on presents the low output level. Subsequent off/on twists of the head within 2 seconds cycles through medium then high output levels. The remaining 4 output modes are strobe, S.O.S., beacon (hi) and beacon (lo). These are activated by going through 2 cycles of the low, medium and high output levels. So an overall sequence available is as follows:

Off > Low > Medium > High > Low > Medium > High > Strobe > S.O.S. > Beacon (Hi) > Beacon (Lo)

Take note that there is no memory functionality so it will always revert to the low output mode first after the light is left off for anything more than 2 seconds.

Beam profile provided produces a medium sized hot spot with a very soft corona tapering off to its spill beam. The beam is clean with no noticeable artifacts. The review sample has an almost pure white tint which is nice. The low and medium output levels seems to be achieved by means of PWM, though the frequency used is high enough for it to not be noticeable in practical usage unless you intentionally wave the light around looking for signs of this. Tests produced a maximum output of 81 lumens which is actually higher than the advertised 70 lumens. Runtime and regulation is maintained very well considering its running on a single AAA battery.

The Good - Clean design and well-machined body. Regulation is maintained well with good runtime. Compact and light weight with clip and lanyard attachment ring options.

The Bad - Nothing significant.

The Relative - Beam is clean with an almost pure white tint. Uses a twist switch. Is able to tail stand.