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Kryptonite Street F-300 front light



A sturdy day-to-night light with decent beam width, added safety features and a pocket-pleasing price tag

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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With 24 hours of illumination, a handy battery indicator and its auto eco mode, Kryptonite's street-focused front light is host to some thoughtful safety additions. While set-up is on the fiddly side, if you're a commuter with a bit of bar to play with, you'll likely find a snug and ongoing home for the Street F-300.

  • Pros: Long-lasting flash mode, safety features, easy on-off for cold hands
  • Cons: Chunky handlebar clamp, lacks pinpoint brightness

The US folk who've been making locks for four decades have set out to illuminate rush hour streets with their China-produced Street Light series. Ranging from 150 to 800 lumen, these USB-rechargeable LED lights are intended to help you see and be seen on the tarmac.

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At 11.5cm in length and 4.5cm wide, the F-300 (F for front light, 300 for lumens) is not as compact as some front lights out there, nor is it the most lightweight at 139g, but it still boasts a neat torch-style lamp with some interesting safety features.

While its six modes provide enough choice for daylight, dusk and darker conditions, they're simple enough to get to grips with quickly. They comprise a high (300 lumens), medium (150) and low (60) steady beam, plus a daytime and night-time pulse (300 and 170) and an economical flash (60).

On test, the F-300's low beam provides enough visibility to ensure I feel seen at night without dazzling oncomers, while its pulses are more pleasant and predictable than some of the more erratic flashing options out there. There's also a memory feature – meaning it switches back on to the mode you left it in. So far, so simple.

Kryptonite says 'this light is great for lighting the way, for most city commuting scenarios', and it's about right. The F-300's output doesn't turn night to day, but it does cast a decent beam on the road ahead. And the light's beam width supports the commuting claim too – its illumination is broad enough to light up road signs (notably wider, in fact, than another 300 I tested, Infini's Tron, full review to come). But what Kryptonite's front light gains in width, it pays for in pinpoint brightness – without street lights, you'd need more power to see the bumps in the road.

To bolster this light's being-seen cred, Kryptonite has added a lateral illumination feature – little light ports to provide more peripheral visibility to surrounding traffic. Handy, it says, for riding across lanes. The windows are small, so output is not terrific, but it's a thoughtful safety feature nonetheless.

Mounting the light, says Kryptonite, is easy. However, the ability to find an appropriate home on your bike for this lamp might just be its main drawback. The bracket-and-ratchet-strap system is simple enough in theory: remove the unit from the bracket using the quick-release button, wrap the bracket round your handlebar, feed the strap through the bracket until you get a tight fit and finally, flip the bracket lever to secure it.

Kryptonite Street F-300 - mount.jpg

How easy it is in practice depends on your setup – specifically bar width, cable routing and whether you've got electronic gearing or not (because if there's no Di2 junction box, you could secure the light to the head tube). With my setup, the F-300's mount system proved a little too cumbersome to allow for a neat attachment. Eventually, and after some frustrated fiddling, I got there. Once on, it provides a tighter and more secure fitting than many rubber-banded options.

A better performance comes from its hassle-free mounting port. The ease with which you can attach and unattach this light from its dock makes grabbing it and running for the train far easier than is often the case. Especially when compared with the rubber attachments that require nimble fingers – tricky on cold commutes.

Battery life is a bonus. A key advantage to Kryptonite's F-300 versus some others out there is its ability to keep you rolling safely for longer between charges, promising up to 24 hours on its lowest 60-lumen setting (Infini's Tron lasts just 8hrs max, pulse or constant). By contrast, though, the full 300 setting only lasts for its claimed 90 minutes (Tron's lasts 2hrs). On test, this was bang on, settling on its longer-lasting 60-lumen 'get you home' flash mode after exactly that.

> Buyer's Guide: The best front lights for cycling

Kryptonite has built in a battery indicator which glows green, yellow or red through a transparent power button, to provide a warning that the lamp has a respective 100, 50 and 25% battery life remaining. When you hit 10% battery, the F-300 automatically switches itself to the economical flash mode in a mission to get you home safely. When you need to recharge, the port allows simple access for a Micro-USB cable – and its lithium battery reaches green, or over 50% full, in under two hours.

The F-300's waterproof capability is excellent, with no signs of water damage after many soggy commutes – and with a two-year warranty, it seems Kryptonite has faith in that too.

At £35.99 it's on a par with other 300s, the Infini Tron and Saturn (full reviews to come), and looks to kick out a bit more light than some higher-number options such as the Blackburn's DayBlazer 400, which is £3 cheaper.


A sturdy day-to-night light with decent beam width, added safety features and a pocket-pleasing price tag

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Make and model: Kryptonite Street F-300

Size tested: 300 lumens

Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

It's aimed at commuting on the road. Kryptonite says 'this light is great for lighting the way, for most city commuting scenarios'. The description is accurate for its intended use and performance.

Tell us some more about the technical aspects of the light?

Kryptonite lists:



FULLY USB RECHARGEABLE - No batteries to buy or replace

Run time up to 24 HOURS

Side illumination ports allow cyclist to be seen when riding across traffic lanes

Memory Function-Light turns on at the last mode it was turned off

Power saving function- 10% power or less, lights will automatically switch to lowest lumen output

Built in battery indicator- Red illumination = lower than 25%, Yellow = 50% - 25%, Green = fully charged

Mode Run Time (Hrs) Lumens

High Steady 1:30 300

Medium Steady 3 150

Low Steady 11 60

DayTime Pulse 8 300

NightTime Pulse 10 60/170

Economic Flash 24 60

Rate the light for quality of construction:

It's not the smallest or lightest, but it still boasts a neat torch-style lamp encased in a smooth, durable and waterproof outer. The easy-on-easy-off is a particular treat, though the handlebar clamp lets it down a bit.

Rate the light for design and ease of use. How simple was the light to use?

The six-mode design had everything I could need from day to night without mode overload. The memory function was an easy way to get going each time I got on my bike, and the button itself is not in the least bit fiddly – and even comes with battery indicator colours. The lateral movement is a nice addition too, though the generous beam width meant I didn't need to use it.

Rate the light for the design and usability of the clamping system/s

Dreamy on-off mounting port, but the bracket itself could be neater and an overall more pleasant experience to fix to your bike. It's quite cumbersome, leaving few options for positioning.

Rate the light for waterproofing. How did it stand up to the elements?

No problems whatsoever, the light performed without exception in all-weather commutes.

Rate the light for battery life. How long did it last? How long did it take to recharge?

Battery life lives up to reports, 90mins on full and 24hrs on flash – with the bonus that it flicks onto eco mode at 10%, again tested and as advertised.

Rate the light for performance:

Beam width was good, though I felt the pinpoint brightness suffered to this end.

Rate the light for durability:

After one month of riding in all weather, there were no signs of this light slowing down. So far, so good.

Rate the light for weight:

There are lighter 300s, but it's definitely not the heaviest either. For its performance, it's about right.

Rate the light for value:

For £35.99 it packs a punch for your commute without hurting your pocket too much. I have spent this much on lights that have conked out sooner – it's a good price for a light that's a good all-rounder.

Tell us how the light performed overall when used for its designed purpose

For commuting under streetlights, the light performs very well. You're visible, and you can see road signs and the road ahead. However, it's not hugely pinpoint bright, so on dark sections more brightness is needed. It copes well with the rain, and provides added safety features – so it's a good all-rounder.

Tell us what you particularly liked about the light

The power save that kicks in when you're under 10%, and the super-easy on-off mounting port for the lamp.

Tell us what you particularly disliked about the light

The chunky bracket, which just didn't fit to my bike neatly.

How does the price compare to that of similar products in the market, including ones recently tested on

It's on a par with other 300s, and similar to some higher-lumen options (which don't necessarily produce as bright a beam).

Did you enjoy using the light? Yes, very much so, once it was on my bike.

Would you consider buying the light? No, I need a brighter option as inevitably my commute will have a dark section.

Would you recommend the light to a friend? Yes, depending on their setup and commuting needs.

Use this box to explain your overall score

For the price point, this light is about bang on. It feels robust, and has some really handy features, from the battery indicator to the low battery flash mode. It loses some points for the chunky handlebar clamp, but quickly gains them back for the on-off mounting port. Once the clamp's on your bike, the light can easily be taken on and off in seconds.

Overall rating: 8/10

About the tester

Age: 0  Height: 172cm  Weight: 60kg

I usually ride: My Scott Foil   My best bike is: Oldie but the goldie, CAAD 8

I've been riding for: Under 5 years  I ride: Every day  I would class myself as: Novice

I regularly do the following types of riding: road racing, cyclo-cross, commuting, touring, general fitness riding, triathlon, audax

Janine is an Ironman triathlete, GB Age Grouper and an Ironman Certified Coach who has raced multi-sports since 2013.

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