Exposure’s Zenith Mk2 body is machined out of anodised 6063 aluminium with plenty of cooling fins to help dissipate heat and keep it cool.
While the light feels very robust and well built, it has a waterproof rating of IP65. This will handle low-pressure water jets but isn’t as waterproof as the best mountain bike lights. Nevertheless, it will fend off a rain shower or two.
Its impressive 2,100-lumen output comes from three white CREE XPL2 LEDs that aim to produce a long-reaching, wide beam to pick up as much of the trail as possible.
There are nine modes to choose from, with each mode having two or three output settings. Exposure claims this enables you to run the light for between one and 18 hours.
One of these modes is called Tap. This feature enables you to tap the light to toggle through the three settings in that mode rather than having to hunt for and press the function button.
You can also select one of three sensitivity settings for how hard you need to tap to change the output.
With such high output from a small light, the Zenith Mk2 uses circuitry that will reduce the power to the LEDs if operating outside their optimum temperature to maintain efficiency. Power returns to normal once the light has cooled.
The 5,000mAh battery is charged with Exposure’s Smart Port+. In addition, you can use the light to charge auxiliary accessories such as rear lights and employ the battery as a power bank.
An LED on the back of the light shows the remaining battery life.
Even with its large battery, the Zenith Mk2 weighs a reasonable 160g.
The light’s circular body is clipped into a plastic mount that threads together. There isn’t any padding to the mount, and a plastic bolt tightens the two parts. A ball-and-socket style joint enables you to angle where the light points.
Exposure Zenith Mk2 helmet light performance
I’m not a big fan of Exposure’s mount. The lack of padding doesn’t make it as slip-free as other mounts. Plus, you must be very careful with the plastic bolt. It was a fraction too large for a 5mm Allen key, which slipped when the bolt became even a little tight.
However, it was far too small for a 6mm Allen key. That said, once it was attached, it didn’t rattle or move out of place.
One helpful thing about the mount is it holds the light close to the helmet, so its weight affects the helmet less when riding by not pulling it around.
What is impressive is the light itself. It packs a big punch for such a small light and does a great job of lighting up the trail. The beam has a decent bright spot at its centre, excellently highlighting the roots, rocks and stumps that litter mountain bike trails.
The beam throw is impressive too, helping to illuminate features further down the trail than a handlebar light. It’s also powerful enough to not be absorbed into the bright handlebar light; exactly what you want and need from a helmet light.
The beam gives a decent spread of light too, so this is one light you could use by itself and still ride reasonably aggressively. It picks out enough of the trail edges to let you know where you should be riding.
Its white light is bright and helps keep your focus. I didn’t notice any prominent or attention-grabbing hotspots, and my eyes didn’t tire using the Zenith Mk2. It highlights the trail well without any negative contrasts.
It’s best to read the manual before using the light, but once you’ve got the basics, it’s easy to operate. I tested the Tap mode and it took a little while to learn the best place to tap the light in order to change power output. This is near the back of the light.
However, the function button is easy to find, and I soon switched to one of the modes where you need to press the button. I found I could more consistently get the light to change modes in this way.
The modes are laser etched onto the light body, which is a nice touch.
The battery indicator turned red quite early, which was a little disconcerting. It turns red when the level’s between 40 and 25 per cent, but you only need to start getting concerned when it pulses red (less than 25 per cent) or flashes red (less than 10 per cent).
I got one hour, 21 minutes of use on full power before the light died, a little better than claimed by Exposure.
Exposure Zenith Mk2 helmet light bottom line
The 2,100 lumens this light produces from its three LEDs is impressive and floods the trail with light that makes riding fast easy.
There is plenty of throw down the trail and a smooth transition from its bright spot, which spreads out to highlight the trail edges well.
There are plenty of mode options, including the Tap feature that means you can hit the rear of the light to change mode, plus a battery indicator light.
You have to pay a high price for this performance, and I’d recommend reading the instructions before getting started.
It doesn’t have the highest waterproof rating on test, but should fend off most rain showers. Some padding on the mount would be good, too.
How we tested
We put six helmet-compatible lights to the test. With prices ranging from £65 to £265, there should be something for everyone’s budget.
The lights chosen here have an output of 450 lumens up to 2,100 lumens. That covers everything from occasional use or as a backup light, to full-on, high-speed riding.
We tested how each light performs riding back-to-back runs on the same trails, comparing beam pattern, LED colour, ease of operation and, most importantly, light projection.
We also timed them all on maximum power to find out just how long the batteries last, and whether they live up to the brands’ claims.
While many of these lights can also be used as handlebar-mounted units, for this test, they were specifically reviewed for use as helmet lights for off-road night riding.
Head to BikeRadar’s round-up of the best helmet lights for our pick of the bunch.
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- Cateye AMPP800 review
- Specialized Flux 1250 review
- Light and Motion Vis Pro 1000 review
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