The head on this light is made of a single piece of aluminum. It's removable and can be easily unscrewed from the main body. Right up the front is a plastic lens which sits slightly recessed from the bezel. The manufacturer advertises is as being coated with S500 Polysiloxane, and also shatterproof. Holding the lens in place is a smooth plastic reflector. The reflector is well polished and does a decent job of focusing output from the LED, though it is just slightly off-center. The exterior of the head is well-polished with a brushed finish. The Type 2 anodizing has a nice, dark gray tone to it. On one side of the head is a protruding piece of metal which has Energizer Lithium branding printed on it. On the opposite side is a metal clip, attached to the head with a couple of Torx screws. The clip is secure enough and is able to hold the light well in most situations.

The battery tube of the light has a thicker than average diameter as compared to other single AA cell lights. This is because the exterior and interior are made of 2 separate tubes. White the external has the same finish as the head, inside sits a polished aluminum tube which makes electrical contact with the electronics. The electronics and emitter are housed towards the front end of the batter tube and held in place by a plastic retaining ring. The middle area of the battery tube has a rubber sleeve which fits very snug. This rubber sleeve provides additional grip and comfort over the aluminum body. Threads at both the front and rear ends are well-cut and smooth. There are 2 rubber o-rings at the front, and 1 at the rear. They sit very snug as well and provide good waterproofing. The light is advertised as being waterproof to IPX7 standards, meaning it can be submerged to a depth of 1m for up to 30 minutes. The tail cap houses a toggle switch which controls the brightness setting. The toggle switch has very short travel and provides a subtle tactile click when engaged. Because of the way the light works, momentary activation by holding down the switch isn't possible. The rubber cap covering the switch is somewhat thing and sits recessed inside the tail cap, this allows the light to stably stand on its tail on flat surfaces. Externally the tail cap has grooves cut all around it for grip during battery changes.

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

The Energizer e² Lithium LED flashlight allow for variable brightness control via simple press of the switch. Holding the switch down ramps the brightness from 100% to 6% which is the lowest level the light is capable of. If the switch is continued to be held down, the brightness ramps from 6% to 100%. This ramping cycle continues until the button is released. There is no memory function, so the lights always turns on at 100% brightness. Lower levels are controlled via PWM (pulse width modulation), the effects of which is noticeable when waving the light around but not in practical use.

The beam profile has some noticeable artifacts and has a noticeable blue tint. Overall runtime, though very well regulated, is pretty disappointing considering the output provided isn't very high either.

Update 02 July, 2008: Due to the auto-shut off feature of the light, I've re-done the runtimes. The spikes in the graph below denotes when light is turned of and on. It does blink prior to shutting off to warn the user.

The Good - Fit and finish are very well done. Ergonomics well thought out and feels comfortable in hand. Easy and straight forward user interface control.

The Bad - Runtime is noticeably lacking.

The Relative - Beam has noticeable artifact and blue tint. Toggle switch does not allow for momentary activation. Is able to tail stand.

Head (front view).

Head (side view).

Head (rear view).

Battery tube (front view).

Battery tube (side view).

Battery tube (rear view).

Tail cap (front view).

Tail cap (side view).

Tail cap (rear view).