The Project Flock Light is designed to make the rider the most visible thing on the road. To achieve this the Flock light uses a unique ‘Biomotion’ feature to shine light downwards onto the riders legs, as well as behind. By highlighting the rider’s legs and their motion, it shows other road users that a person is riding, and that it is not just a red dot up ahead. It enlarges the lit area, making the ‘object’ seem bigger too. There is also a pool of light on the road beneath the rider.
> Buy now: Project Flock Light for £64 from Project Flock
The Flock Light has a really interesting idea at its core – namely that we as humans have evolved to notice other human or animal movements and shapes. By illuminating the rider’s legs, this tendency can be exploited.
It is also a very good light. I thought that the slow pulse (2-3 second cycle on the Solid Biomotion setting) was really effective at getting noticed, both in daylight and at night. The Solid mode worked well in twilight too. However, the biggest surprise was how good the Eco flash was at night. I thought that it’d be too dim to be worth bothering with – but no, it was clearly visible, and from a distance. It paired nicely with a decent helmet rear light. You can see this combination on the video clip.
My first night ride out with the Flock was when it was still cold enough to need bib tights. When I put the light onto my friend’s bike, so that I could observe it in action, I was a little disappointed. He has really good reflective panels on the calf area of his bibtights. I think that I expected to see more reflection of the red light than I did. Maybe the black bibs absorb the light more? A couple of rides later we were firmly into warmer spring weather and shorts were being worn. This made quite a difference in the visibility of the Biomotion light. It seemed to show up better on bare skin. I did like the pool of light spread onto the road too. When hanging back to observe the light again, I found that it was the gentle pulse from the solid Biomotion rear light that was most noticeable. The rider’s legs, and pool of light on the road, became more visible as I got closer. You can see the effect shown on my other video clip.
When I rode with an Altura Nightvision Electron jacket a few years ago, I was really surprised how cautious and careful drivers became around me. I put it down to the shoulder-to-waist lighting strips showing the upper half of a rider. It made me more visible than normal, particularly when just using a rear light and a helmet light. Often the upper half of a rider is invisible to a following car, especially if dipped lights are used. A similar effect is employed here, which is enlargement of the lit area. In addition, the movement of the rider’s legs is visually unusual when they are lit up. Whilst I love the idea of this effect, I didn’t quite sense the same feeling of care/astonishment from approaching drivers as when I wore that jacket. One thing to note is that if you ride with a single or pair of panniers is that your leg(s) won’t show up. However, you will still get the pulse effect from the rear facing part of the light.
The battery life is broadly as stated. I found that Solid Biomotion gave me 3h45m of runtime (stated as 4h by Project Flock), yet the Group Biomotion mode sailed past its claimed 6h by an additional 45 minutes. The Eco Flash mode is a claimed 100 hours and it made me wonder why the light isn’t programmed to automatically drop from Solid or Group to the Eco mode when there is only 5% battery left. It would be a great ‘get you home’ feature – and one that many lights now employ.
> Best rear bike lights 2025 — boost your visibility day and night with a bright beam at the back
The five LED battery gauge was a good feature, and shows up when the light is switched on and off. It also shows whilst charging the unit. The light is IPX6 weatherproof rated. This means that it can get wet, either in a light spray or with exposure to the rain. It is also dust tight. It hasn’t rained much recently, but the Flock was fine under a shower. The port is a good fit but the tab to pull it open is pretty minimal. It is quite hard to pull free with a thumb and finger pinch. The Flock has a USB-C port and charges from empty in 3h using a standard 5V 1A computer USB. This is quite a lot longer than Project Flock claim as they state 1.5 to 2h. I did a full charge twice and both times it was 3h. Interestingly, they also state that a USB-C to C cable can’t charge the unit, only USB-A to C – yet I tried it and it worked. This is not recommended by Project Flock though.
The bracket is nicely made and uses a petite quarter-turn attachment. There is a little play when the light is attached, but it held without issues during the testing period. The seat post clip is supplied with three lengths of rubber straps and will fit round D-shaped and aero seat posts without needing to change an insert. Project Flock also sell saddle rail and Specialized Power saddle mounts, as well as a solid round seat post bracket. However, as cute as the small quarter-turn mount was, can we all just agree to use the Garmin standard? It would make life simpler wouldn’t it?
Overall, this a very good light with much to commend it. The Solid Biomotion mode is clearly visible from behind. The side lighting is also very clear. The surprisingly good Eco Flash mode was not expected either. The Biomotion feature is a really interesting idea that seems to work best shining onto bare skin rather than black leggings. The battery life and charging is fine, just not great. Overall this is worth considering though.
Verdict
A good quality light with an interesting USP, however it’s not as dramatic as you might think
> Buy now: Project Flock Light for £64 from Project Flock
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road.cc test report
Make and model: Project Flock Flock Light
Size tested: 5 – 120 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?
The Project Flock rear light is aimed at cyclists riding ‘dimly-lit paths’ through to ‘bustling city streets’. As the aim is to make the rider appear to other road users as ‘a human on a bike’ rather than ‘just another red dot on the road’. The primary audience will be road, commuter or utility riders. However a rear light is a rear light and as such any rider needing rear illumination could use the Flock.
Tell us some more about the technical aspects of the light?
There are four lighting modes outputting 5 to 120 lumens. The battery life is stated as being between 4 and 100 hours
Specs:
NOTE: USE ONLY A USB-A TO USB-C CABLE (AS SUPPLIED). USB-C TO USB-C CABLES WILL NOT CHARGE YOUR FLOCK LIGHT.
LED: 3 x CREE XPE-RED
Weight: 57g (2 oz)
Waterproof rating: Yes, IPX6
Dimensions: 74mm (L) x 35mm (W) x 28mm (D) ( 2.7′ x 1.3′ x 1.1′)
Light Modes & Run Times: Solid Biomotion 4hrs, Group Biomotion 6hrs, Day Flash 12hrs, Eco Flash 100hrs
Lumens: 5 – 120 lumens
Viewing angle: 300 degrees
Charging time: 1.5-2 hrs with USB-C
Mounting: Seat Post mount, compatible with standard, most aero and D-shape seat posts
The light feels well made using good quality plastics. It has an IXP6 waterproof rating with a good fitting port cover.
It is very easy to use and understand. One button will power the unit on with a long press, then the four modes are cycled through using short presses. When powering the light down with a long press, it will show the amount of battery remaining with its five LED display.
The bracket will work on most seat post types, including round, D-shaped and aero without needing to change the rubber insert. As well as working on a regular round seat post it fitted an older style Campagnolo aero seatpost fine. A quarter turn fixes the light onto the bracket. Very easy. There is a little play between the bracket and the light but it held securely throughout testing/riding. The light comes with three rubber bands that should be able to fit to most seatposts.
Also available to buy are three other mounts: a solid round 27.2mm seat post bracket, a saddle rail mount and a power saddle or ‘SWAT” mount.
The Flock is IXP6 rated which means that it is protected against water ingress from any angle. There were no issues from light rain, or running under a tap. It has been a pretty dry period of weather during testing. The rubber USB port seems well made and fitted securely. It is a little fiddly to release the port with a finger tip pinch.
It has a decent battery life for its size. With a stated life of either 4, 6, 12 or 100 hours depending on the mode selected. The Solid Biomotion claimed 4 hours and I found that it lasted for 3.75 hours, but the Group Biomotion (6 hrs claimed) actually lasted for 6.75 hours. When charging the unit with a USB-C cable and using a 5V 1A source the battery charged from flat in three hours and from 5% in two hours and 50 mins. This is quite a lot longer than the claimed 1.5-2 hours recharge time. Project Flock didn’t state whether their time was measured from a higher wattage source however.
It is stated that you can only charge the light using a USB-A to C cable, yet when I used a C to C cable plugged into a USB-C travel plug it worked. I have seen reports that say that only A to C worked for some individuals. Best thing is to assume that a USB-A to C cable is needed to charge.
This is a good light with very good side illumination. The downward firing LEDs are also good but maybe not as dramatic as I’d thought they would be. The solid mode actually pulses fairly slowly but it does make it nicely visible. The surprise was the Eco Flash. I thought that it would be a bit dim. When using it on dark country lanes it showed up much better than the specs would have you think.
It’s a shame that when the battery drops to say 5% left that it doesn’t automatically drop to a lower level to extend the lights’ illumination. I’ve ridden with a few lights recently that do this, and as a ‘get you home’ feature it’s rather good.
It feels well made in the hand. The plastic has a textured finish to it and feels robust. No brittle or hard plastics seem to have been used here.
At a stated 73 grams (I measured 75 grams) for the light, bracket and medium rubber strap, it is a reasonably light weight for its output. The lamp section is stated as 57 grams, although I weighed it at 61 grams. For comparison the Exposure TraceR (mk 2) is 50 grams for the light and seatpost bracket.
At £65 plus £10 shipping to the UK, it certainly isn’t cheap, but neither is it wildly expensive for a decent quality light.
Tell us how the light performed overall when used for its designed purpose
As a rearward firing light it is very good. The gentle pulse with the Solid Biomotion mode is really effective, and visible from a long way back. Equally the Eco Flash was surprisingly good and visible, despite appearing dim when looked at directly. The Day Flash mode was powerful and I had no qualms using it for day riding.
The other half of this light is its Biomotion downward firing LEDs. I found that the effect was not as dramatic as I expected it to be, although it did work fine. It also seemed to work better when shining onto bare legs as opposed to black winter leggings. I liked the pool of light that it spread onto the ground too.
Tell us what you particularly liked about the light
Battery gauge showing at switch on and switch off. It also shows when charging. Light can be used whilst charging too, which could be useful in certain circumstances.
Tell us what you particularly disliked about the light
Slight play when attached to bracket felt annoying, albeit in a minor way.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
My two longstanding recommendations for (just) rear lights are the Exposure TraceR and Knog Cobber Mid Rear lights. This is from years of night riding and observing what works well and is highly visible. The TraceR can be bought for £45, with a Reakt version that is £75. Exposure are British made and well supported if there is an issue or a service required. Its day flash is fantastic. The Knog has a very visible block of light with excellent side vision. I’m always happy to ride with either. However my go-to now is a Garmin Varia radar and rear light (RTL515). Whilst the light is not quite as good as the Exposure and Knog, the ability to be alerted of approaching vehicles is a game changer. I rarely ride without it now. At £170 the Garmin is expensive, so the cheaper Bryton Gardia R300L is a good value alternative.
Did you enjoy using the light? I did. I felt well lit from behind, and visible
Would you consider buying the light? No – mainly because I value a rear radar/light very highly.
Would you recommend the light to a friend? Yes. Although I’d recommend a radar-light first
Use this box to explain your overall score
Firstly this is a very good light. At night it is clearly visible, and its slow pulse draws your attention. The Eco flash was a surprise as to how good it was at night. The Day Flash is also very good. The Biomotion feature was not as dramatic as you might expect, but it is good nevertheless. It seemed to work on bare skin better than with black cycling leggings. The battery life is fine with the Biomotion function operating, and really good without. The charging took significantly longer than stated however.
About the tester
Age: 56 Height: 180cm Weight: 66kg
I usually ride: Condor Fratello 55cm My best bike is: Gios Evolution 55cm
I’ve been riding for: Over 20 years I ride: Every week I would class myself as: Expert
I regularly do the following types of riding: commuting, touring, general fitness riding, fixed/singlespeed, mtb, General road riding is most common
1 thought on “Project Flock Light”
“How does the price compare
“How does the price compare to that of similar products in the market, including ones recently tested on road.cc?”
no mention of the ‘Magicshine SeeMee 300 Smart Tail Light’ you reviewed last year, which I think is a great light; similar ‘OptiTracing’ to this ones ‘Biomotion’; lasts longer maybe & is much cheaper