Exposure Diablo Review

While the Exposure Diablo light is sold primarily as a helmet light, it also works extremely well as a super lightweight and incredibly bright handlebar light. This was my weapon of choice throughout last winter, and I used it every day for my commute in all weather conditions through dark country lanes.

The latest version is the Mk3. The review model is actually the Mk1 but the general form factor and features are the same. I shall highlight the differences between the Mk1, Mk2, and Mk3 throughout the text, and when I get hold of an Mk3 model I shall post some updates where applicable.

Exposure Diablo Design

Like all Exposure lights, the Diablo oozes quality. It features a cool CNC machined aluminum casing with an anodized finish. The light is just four and a half inches long and the diameter at the widest part is a little under an inch and a half.

According to my scales, it weighs just 107g including the lanyard clip. The Lithium-Ion rechargeable battery is contained within the unit and a mains charger is supplied.

The charger with the Mk3 includes a USB lead so the light can also be charged via any convenient USB socket. Extra USB leads can be purchased separately (for example you could leave one at work).

The light is well sealed from the elements. The only place water could possibly get in would the socket where the charger or accessories are connected.

It would be nice if a rubber plug was supplied for when the socket is not in use(*). That said, it’s a light for cycling, not scuba diving, and I used it in some torrential rain showers last winter without any problems whatsoever.

Helmet Mount

The helmet mount should fit virtually any helmet with air vents. It consists of two circular discs with a nylon bolt to hold them together. Within the top disc is a ball mount which allows the light position to be tweaked as necessary. Two nylon bolts of different lengths are supplied to ensure the light will fit a helmet of any thickness.

A lanyard is also supplied which can be threaded through the helmet vents to provide extra security, though the light clips into the mount with quite a tight fit so are unlikely to drop out. The lanyard has a quick release catch to allow it to quickly be detached from the light.

Handlebar Mount

While the Mk1 light included the handlebar mount as well as a helmet mount, the Mk2 and Mk3 models are only supplied with a helmet mount. That’s a shame, but the handlebar mount can be purchased separately.

It’s another nice piece of engineering and has a quick-release mechanism which is a little fiddly but can be operated with gloves. The handlebar mount has a spacer and silicone strip so that it can mount to 25.6, 26 or 31.8mm bars (i.e. all the usual sizes).

If you choose to buy the handlebar mount for use with this light, make sure you get the one with the clip (which fits the Joystick, Diablo and Spark lights).

A much cheaper cable tie bracket is also available but this is nothing like as good as the quick release version.

Operating Modes & Battery Life

The Light has one button on the back. Press it twice quickly and the light switches on in high power mode. Then single presses of the button cause the light to cycle through its high, medium and low settings. Pressing and holding the button for a short time sets the light in a somewhat irritating but eye-catching flashing mode.

Pressing and holding the button for longer time turns the light off. The button is easy to operate with gloves but not so easy as to accidentally switch on when carried in a bag. A single LED on the rear provides an indication of the remaining battery life and progresses from Green to amber to red to flashing red.

The light automatically drops to a lower light mode to preserve batteries when they’re almost empty. I found the light easily exceeded the advertised battery life of 1 hour in high power mode. The charge time is around 4 hours.

Beam pattern & Brightness

On the highest setting, the Exposure Diablo is very bright and allows you to ride on unlit country roads with confidence. The highest setting is probably overkilled if you’re riding in town on lit roads where the medium or even the low settings will be fine. The beam pattern is round with a very focused center and a good spread.

(Note the beam pattern for the Mk3 model will likely be slightly different as it features 3 LEDs rather than one. I’ll post an updated beam pattern if I can get hold of an Mk3 model). Also, bear in mind the Mk3 is approx 40% brighter than the Mk1!

Exposure Diablo MK3 Updates

The latest version (Exposure Diablo MK3) includes a number of improvements as outlined in our Exposure Lights news post.


The Exposure Diablo is a superb exposure bike light. It’s extraordinarily bright for such a small lightweight package. Battery life is not as long as the other (heavier) Exposure lights but it should be fine for most purposes. Exposure Lights are not cheap but they are of very high quality.

If you want the brightest helmet light or you care about the weight of your light you can’t go wrong with the Exposure Diablo. This is our choice of best lightweight front light on our best bike lights page.

Where to buy the Exposure Diabo

The official manufacturer website page for the Exposure Diablo Mk3 can be found in AMAZON.