See.Sense Icon 3 rear light review

Machine learning meets road-riding visibility

This competition is now closed

By Ashley Quinlan

Published: July 7, 2023 at 1:00 pm

The See.Sense Icon 3 combines a bright 350-lumen output with built-in reactivity for changing conditions. It also performs a civic duty for road planners.

In principle, the Icon 3 is an impressive rear light, once you’ve worked out its quirks.

Although it’s not perfect, it packages up enough good features to make it a compelling rear-light choice.

The Icon 3 is something of a rear light on steroids.

It throws out a huge 350 lumens in its maximum brightness setting, via custom-made COB (chip-on-board) LEDs, plus two additional LEDs.

It’s the most powerful rear light I’ve ever tested, and outshines even the Lezyne Strip Drive Pro Alert 300. That said, Cateye makes the Viz450, showing that even the Icon 3 isn’t the outright brightest on paper.

The COB LEDs light up an internal ring. When fully illuminated, this reflects against the lens’ outer cover. The result produces a ‘full board’ of light, which is claimed to be visible through a 270-degree arc.

Two additional LEDs flash in a disruptive manner alongside the board to improve visibility.

There are also five small indicator LEDs across the top of the light that show the battery level to the nearest 20 per cent increments.

The Icon 3 has three modes accessible via the central button: constant, flash and eco [flash], and can be operated by the single button or via See.Sense’s app.

If you solely use the light via the button, it reacts automatically to your surroundings. Used in constant mode, the light sensor spools up to higher brightness levels in bright light, and dims when night falls.

In the flash and eco modes, the flash rates increase in frequency upon a change in conditions (ambient light, motion or a combination of the two).

If you opt to use the app to control the light (via Bluetooth), you can operate it and choose from six modes (the other three effectively offering other patterns of flash).

From there, you can also choose to switch on features, such as brake mode, super visibility, light sensing, the built-in ‘get me home’ safeguard, and a theft alarm.

Each works as you might expect, effectively powering up and/or randomising the output to boost visibility, whether you’re braking or your surroundings change.

The ‘get me home’ mode is claimed to guarantee a final hour of life from the light when the battery runs low (20 per cent).

The theft alarm notifies you via your phone if your bike has been moved (say, for example, if you’re in a coffee shop with the bike outside and in Bluetooth range).

The app also has the ability to send out a crash alert to an emergency contact, and record riding stats, with the light gathering data on your ride behaviour.

While the light responds to changes in conditions, it will (with your permission) send anonymised data back to See.Sense.

See.Sense’s CEO, Philip McAleese, tells me the data is used to help road planners with infrastructure development, highlighting potential high-risk areas, while the brand also sees interesting data when it comes to rider habits.

You can even file a personal request via the app for infrastructure development.

The Icon 3 features a simple quarter-turn mount, which wraps around a seatpost with a standard rubber band.

It charges via a short USB-A to USB-C cable (the port in the back of the light is USB-C).

It costs £100/€115/$120, which is expensive when compared to most of the best rear bike lights.

Although I’ve tested the bewilderingly bright Lezyne Strip Drive Pro Alert 300 in recent months, the Icon 3 is arguably even more impressive with its output.

Whether you actually need 350 lumens spread across the COB and standard LED array is open for debate, but there should be no excuse for being missed by a fellow road user.

On constant mode, the light spools up to maximum brightness either via its sensor or manually via the app to provide brightness that outshines even car LED brake lights.

Any of the flashing modes are ‘shocking’ enough to draw attention, while the Icon 3 reassuringly increases the intensity when your surroundings change.

McAleese tells me the light is, in fact, learning the behavioural characteristics of the rider and gathering data about its surroundings from the moment it’s switched on.

It sounds a bit I, Robot combined with a small dose of Big Brother (should you opt in to sharing your data), but the idea is to enable the light to respond to your riding, rather than a pre-determined set of stimuli (like the Lezyne).

So, one Icon 3 light won’t ever be equal to another, because it’s learning how you ride and responding accordingly.

I have two samples of the Icon 3, which have been used in different scenarios.

When I switch them on side by side, one is now slightly more sensitive to changes in my environment than the other (the one I’ve used for commuting, over the one used solely on test and club rides, which has presumably grown used to a more consistent style of riding).

I also found the alarm sensor works well. Your phone needs to be in range of it (and ideally not behind any thick stone walls, as I discovered), but it performs well by giving you a notification when the bike (the light) is moved.

See.Sense says it has made arming and disarming the alarm a manual process (as opposed to it automatically coming on), which – as long as you don’t forget – is a good thing.

It has also desensitised it versus previous iterations to ensure you’re not getting constant notifications on your phone when a small breeze wafts over the bike.

That said, there are quirks to be aware of that influence the user experience.

While the Icon 3 is responsive (almost) however you choose to use it, it can be unpredictable in its employment of power.

This is good in the sense that disruptive changes to output probably boost visibility to other road users. However, it can be overly sensitive, while at other times it doesn’t seem to react even when I brake hard and come to a full stop.

McAleese explains that me fiddling around with the light for a while before installing it on the bike may have unduly influenced the machine-learning element of the Icon 3, but also says most of that memory is wiped with a full charge.

Although it works as I’d expect most of the time, sometimes it doesn’t respond as it arguably should.

This is in stark contrast to the Lezyne Strip Drive Pro Alert 300, which responds more readily and predictably with its in-built sensor, but at a cost of battery life.

In any flash mode, the Icon 3 has more than enough battery power to see you through an all-day ride. It claims 16 hours with reactive settings switched on.

Naturally, burn time will depend on how often it reacts, but broadly speaking from experience, I think 16 hours is achievable. Closer to 12 hours is probably more realistic if you’re using the light in stop/start traffic more often.

For the record, Eco mode is said to be able to deliver 40 hours of life, which seems in the right ballpark given the unknowables at play.

However, the constant mode is limiting, especially when it’s responding to ambient light.

For the most part, it will spool up to maximum brightness in the day and twilight. For many club riders, the two-hour claimed burn time will be too short, even accounting for the extra hour from the ‘get you home’ mode.

I was caught out on a couple of rides, where the light simply switched itself off without warning, the battery completely drained. This happened at around the 1 hour 30 minute mark on each ride (the ‘get you home’ mode wasn’t activated).

See.Sense has also gone to the admirable trouble of minimising packaging and ensuring it’s recyclable.

The downside is there are limited instructions included (and no QR code to deeper instructions online), which left me needing to use intuition to work out exactly what the light was doing at a given moment – not easy when the light isn’t totally predictable.

However, these flaws are relatively small compared to the holistic performance of the See.Sense Icon 3.

The design is neat (if a little divisive in its rectangular shape), and the bracket is small yet secure – it’s easy to fit and remove both the light from the bracket, and the bracket from the bike.

The See.Sense Icon 3 is a high-quality unit, which puts out an enormous amount of light.

Its modes are attention-attracting, and there are some smart features within the light that help it to adapt to your style of riding. These could also – permissions allowing – potentially feed road developments.

The modes might not be totally predictable, and the tendency for the static mode to crank up to full brightness can reduce battery life.

However, overall, the Icon 3 is a light I’d be happy to continue using daily.

Senior technical editor

Ashley Quinlan is a senior technical editor for BikeRadar, covering all things road and gravel. A trained journalist, he has been working in and around the bike industry for almost a decade, and riding for much longer. He’s written for road.cc, eBikeTips, RoadCyclingUK and Triathlon Plus magazine, covering the latest news and product launches, and writing in-depth reviews, group tests, buyer’s guides… and more. He’s also worked in PR for some of the industry’s biggest brands. A roadie at heart (who often casts an interested gaze at gravel and XC mountain biking), Ash has been told that he’s best used as windbreak thanks to his 188cm, 80-plus kilogram build. Despite this, he loves spending time in the mountains scaling cols and is a repeat finisher of the Étape du Tour.