Lezyne Femto Drive Duo

For such a small lumen count, the Lezyne Femto Duo is quite a punchy light for sitting atop your helmet. It's simple to use, should fit to any vented helmet, and the batteries last for ages. Also, I haven't had any issues with water ingress like we had on previous test models. There is some tough competition out there, though.

We last reviewed the Femto Duo back in 2016 and Dave's only real concern was that, with both the front and rear lenses also being a switch, they allowed water to enter the unit in heavy rain.

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In the last six weeks of testing, I haven't had any issues with that, even when testing it under the bathroom shower. I've fired water at it from all angles and even submerged the lens part of each end in water, with no ingress.

Lezyne doesn't give an IP rating for waterproofing so there is nothing to really gauge whether they should keep the water out, or to what level. Maybe I've just been lucky so far, but you could always try not to use the switch in the rain, and check for water inside the lens after riding – at least that way you can dry them out before any damage is done.

As for the light itself. Well, it's basically a front and rear Femto light, joined together by way of a composite bracket which allows you to run a Velcro strap through it so you can attach it to any vented helmet. Once in position, the light is held in place securely.

Operation, as I've mentioned, is controlled by way of pushing the lenses. Press and hold to turn them on or off, and apply just a small press to scroll through the modes.

Each 'end' has three Flashing modes, each one faster than the previous one, plus Pulse and Solid.

A run-time of 30hrs is given for the constant Solid mode, and 60hrs for anything that flashes or pulses. It's hard to gauge, as the Duo uses two CR2032 batteries either end, which I know from experience can be affected by temperature – the cold can shorten their lifespan.

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The front light pumps out 15 lumens, the rear 7 lumens. Both ends of the Duo can be operated individually, so you can run whatever combination of flashing or constant pattern you like.

The front light puts out more light than you'd expect, and though you wouldn't (and couldn't) use it as a main light, it's bright enough to be seen on the floor, and I found it handy to be able to glance back at the cassette if I wasn't sure what gear I was in on very dark roads.

The rear one is still bright enough to be seen by, helped by the fact that it's elevated.

Value

The Femto Duo is priced at £28, which is in line with something like Brightside's Topside Helmet Light at £29.99.

That's capable of putting out up to 100 lumens, though, while still offering decent burn-times, and it's rechargeable. It also gets an IP65 rating, meaning it'll cope with heavy jets of water. That's a lot of light for the money, and makes the Femto Duo look pricey and a little outdated in comparison.

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Topeak's Headlux isn't that bright, but as a be seen light it still does a decent job. It also uses CR2032 batteries and offers good burn-times. It'll set you back £18.99.

Conclusion

Overall, the Femto Duo is a decent performer, as long as it continues to keep the water out. It's got some tough competition for the money, though.

Verdict

Compact 'be seen by' light, but it's not the best value out there