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Cateye Viz 300 Rear Light



Lots of power for the money, viewing angles are excellent and run times are strong
Great viewing angles
Good burn-times
Build feels solid
Slightly fiddly mount
Flash patterns are pretty hectic

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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The Cateye ViZ 300 can get extremely bright, is visible from as many angles as you could ask for and lasts really well on each charge. The price is good for its output, too – it basically does everything you could sensibly want.

Nothing is perfect, of course, and the ViZ has niggles. Two of its four modes are on the frantic side, the full-power 300lm flash is arguably obnoxious on all but the brightest days, and the clamp is a bit clumsy.

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While the modes can be changed (and the unit remembers which one you were in), the strap design can't. To be clear, it's excellent once installed – stable, secure and a good angle – so if you're going to leave it there, it's all good.

You'll need your own decent-length micro USB cable if you plan to do so, though, as the supplied one is the usual stubby little thing that won't be reaching your seatpost.

Take the ViZ off to charge it (or stash away in a bag), though, and both the ladder strap and the chunky rubber bung fall off very easily. Being so soft they tend to do it silently too. That's tricky; lose one and you can't mount this anymore.

2021 Cateye Viz 300 Rear Bike Light - mount.jpg

At least the black bracket clips to the light securely, and the mounting is square, so the light fits portrait or landscape. Rather cleverly, the squeeze when it's all fitted locks a little tab so the lamp can't jump out while you ride.

Unfortunately, that also means you can't leave the whole mount in place and just remove the lamp for charging, so you're back to trying not to lose bits.

On the upside, the mount spreads to fit all kinds of posts (including kamm tail), and angles the lamp pretty much vertically.

Water resistance is rated to IPX4, and while that's not the highest out there, the ViZ was untroubled by rain or spray during the test. Both the button and the charging port are protected by silicone, and while having the port underneath the unit puts it in line for spray, gravity ensures it won't pool and seep in.

2021 Cateye Viz 300 Rear Bike Light - charging port.jpg

Modes and run-times

The shortest claimed run-time is a useful 5hrs, and that's pretty accurate – surprisingly it's not for the eyeball-grilling 300lm 'Daytime Hyperflash,' which can signal nearby planets (probably) for up to 10hrs, but for the 30lm Constant mode.

That doesn't sound very bright, but the 30lm glow from all three LEDs through the transparent case is actually pretty eye-catching outside of bright sunshine or night-time commutes.

I shunned the 30lm Flashing mode (though it lasts a claimed 45hrs) as the flashes are such short bursts, and the pace just high enough to make it look (at least to me) like it'll almost instantly annoy following drivers.

I also avoided the Daytime Hyperflash in anything but strong sunlight, because it's so bright and so luridly chaotic it's like riding around on a distress beacon. Again it's a personal choice, but I don't want to give the worst drivers another excuse to throw a cretinous shut-your-eyes pass.

> Buyer’s Guide: 22 of the best rear lights for cycling

I found the final mode – Group Ride – the most useful. At 100lm it's bright but not tactical nuke bright, and it's actually easier on the eye than the dimmer flash as it always seems to leave something lit.

It's hard to tell exactly, as looking at this straight on can literally make your eyes hurt, but Group Ride appears to switch each LED between two brightnesses, and leave either two dim or one bright one on at all times. Thus it's never fully dark, and consequently easier on the eyes (I was looking from the side, in case you were wondering...).

With an 8hr claimed run-time from the 800mAh li-ion battery, Group Ride is very usable too. I certainly never had it shut down even after multiple rides, as there's ample opportunity to top up before it gets critical (and a red warning light at 1hr left, when it also switches to a special power-saving flash pattern).


At £39.99, the ViZ 300 is cheaper than many lights of the same power. The Lezyne Laser Drive gives 250lm and is £65, for instance, though that also draws your own bike lane on the ground for you.

The Moon Sirius Pro is even brighter at 350lm and built really solidly, though it's complicated, and £54.99.

If you don't typically run lights on bright days and find 100lm enough, you can save a bit with something like the Gemini Juno 100 at £29.99, though that lacks the kind of side visibility this gives.

In fact, the ViZ 300's spread means you can check it's on with just a glance down while riding, which is something I appreciate. It's a feature it shares with my 270lm Knog Cobber (still in constant use two years on), and though the Knog's broad pinboard of tiny lamps is considerably easier on the eyes, it needs charging every ride and is now £78.99.


On the bike the CatEye ViZ is simple, secure, effective and long-lived. The clamp needs a bit more attention once you remove it – and if you don't use lights on bright days it's a bit excessive – but other than that it's very good; it gets the job done well.


Lots of power for the money, viewing angles are excellent and run times are strong

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Make and model: Cateye Viz 300 Rear Bike Light

Size tested: 300 Lumen

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?

Cateye says: "Pumping out an attention-grabbing 300 lumens with OptiCube lens technology, the versatile ViZ300 stands out with the power of Daytime Hyperflash mode and the friendliness of Group Ride mode."

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

Cateye lists:

3 LEDs (300 lm)

Highly visible during daytime

300 degree visibility

Long rear beam projection

OptiCube lens technology

Lithium-ion rechargeable battery

USB rechargeable (Micro-USB cable included)

Low battery indicator

4 modes Charging time: 3h

Mode memory function

Battery Auto Save (The mode automatically changes to flashing when the battery power gets low.)

New seat post bracket SP-15 which fits contemporary (kammtail) aero seatpost

Snap System

Rate the light for quality of construction:
Rate the light for design and ease of use. How simple was the light to use?
Rate the light for the design and usability of the clamping system/s

Three-part clamp design feels rather clunky, but once installed it works very well.

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

No issues with rain or spray.

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

Feels solidly made – arguably the biggest risk is losing part of the mount when you're charging/storing/transporting it.

Rate the light for weight:
Rate the light for value:

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

Very well – reliable and easy to use.

Tell us what you particularly liked about the light

No opaque parts for great coverage, long run-times, solid build, very bright.

Tell us what you particularly disliked about the light

Potentially too bright and frantic, clumsy mount design.

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

It's £15-£20 cheaper than many lights of the same brightness.

Did you enjoy using the light? Yes

Would you consider buying the light? Yes

Would you recommend the light to a friend? Yes

Use this box to explain your overall score

This is bright, visible across very wide angles, and reliable both in burn-times and physical solidity. Though the three-part mount feels clumsy and is begging for you to lose a piece when not on the bike, once on your seatpost it's very secure.

Overall rating: 8/10

About the tester

Age: 48  Height: 183cm  Weight: 78kg

I usually ride: Vitus Zenium SL VR Disc  My best bike is:

I've been riding for: 10-20 years  I ride: A few times a week  I would class myself as: Experienced

I regularly do the following types of riding: general fitness riding, mtb,

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