Like this site? Help us to make it better.


Giant Numen Plus Link TL rear light



Useful second light if you have a compatible Giant helmet

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.

What the scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

The Giant Numen Plus Link TL (it stands for Tail Light) is, as the name suggests, an integrated rear light designed specifically for Giant's own range of helmets. It's a bit of a niche product in some respects and many standard lights can be persuaded to fit road and trail helmets too.

Magnetic attraction

The Numen Plus Link TL attaches neatly to Giant helmets via magnets, one on the light, the other hiding behind the Giant branded panel. These aren't the most powerful connection but it's firm enough for most people's needs and some mixed terrain shenanigans hasn't dislodged it. You can also mount it on the seat post, as per the photo above.

Buy Giant Numen Plus Link TL
Find a Giant dealer


It also uses magnets to link with the charger. This is neat from a designer's perspective but commits you to not losing Giant's cable. On a day to day basis, this isn't a problem but will require a more disciplined approach to refuelling; you can't use any old micro-USB cable like those almost universally used with phones. It takes three hours to charge from fully depleted.



This is a relatively sleek design but blessed with plenty of peripheral presence. Twenty lumens is a decent amount if light for most situations, although especially for a light on your helmet. Over the past few years, I've experimented with helmet-mounting 50 and 60 lumen models but found them unnecessarily harsh and more likely to dazzle other road users.

It's brighter than numbers alone would suggest, thanks to 'chip on board' (COB) LED construction technology, which crams multiple emitters into the same space, increasing their intensity and impact. A heat sink is employed to regulate temperature and increase their useful life.

Auto Engagement

To eke out as much run time as possible there's a sensor that automatically switches the light on/off according to light conditions. Nothing new, Shimano Nexus dynamo switches had this function some 17 years back. Both required some trial and error moments, although given the unit's location, you'd need to be doing some serious green laning to obscure the sensor and therefore constantly engage the switch.

Read more: Buyer's guide to rear lights — make sure you're seen at night


Talking of engagement, the switch is a sensibly sized rubberised affair that is intuitive enough to operate in gloved hands but requires a definite press, so accidental engagements have not been an issue.

Held for two seconds and it comes alive, then prod firmly to cruise through the four modes. At its most basic, we only need flashing and steady options but four settings will suit most situations. We have high and mid constant settings, which appear to be 20 and 10 lumens respectively and two strobing: flashing and 'patrol'. The latter is essentially a quick pulsing.

Giant Numen Plus Link TL - bracket.jpg


Giant don't list an IPX rating but suggest it's water-resistant enough to fend off heavy rain. I've not had any problems and subjected it to my usual garden hose test without incident. However, a few days into testing the press-fit rubberised switch cover came adrift, leaving circuitry and other sensitive electricals open to the elements. I'm confident ours was simply a rogue model and decent retailers would simply replace under warranty.

Run times

Giant don't break this down by mode but cite a middling five hours maximum. That's disappointing when pitted against similarly priced competition, like the Cat-Eye Rapid Micro X[/url. Admittedly, the Micro X a 15-lumen unit but it will flash away for almost 30 hours. Our Giant has returned 4 hours 54 minutes in flashing and patrol modes. High modewas good for 1hr 30min, mid for 2hr 30min. Those are fair numbers given the overall performance and for secondary lighting but this reinforces the point that you'll need to be disciplined about recharging.


While not daylight modes in the commonly accepted sense, flashing and patrol were surprisingly conspicuous in cloudy/overcast conditions, hence I tended to run them by default. The auto engagement function is reliable enough and while there was some occasional disparity between its optics and my eyes, the Numen Plus Link TL is intended as secondary lighting and I never felt the need to override it.

Along pitch black lanes, approaching riders reckoned they could spot me from around 200 metres: impressive. Given competing illumination, expect to be visible from around 100 metres through town. The 180 degree arc provides some welcome presence when entering the flow of traffic or tackling roundabouts. Twenty lumens is sensible in this context too; easily enough to snare and maintain driver attention but without dazzling at close quarters.

Of the constant modes, I've erred towards the highest through town, although it does put quite a significant dent in the run time. Expect to be visible from 70 metres through town, 100 on the open road and relatively clear nights. The mid steady mode is visible from 40-50 metres in town, 70/80 on the open road, and seems a good choice for group riding.

Overall, I've enjoyed using the Giant Numen Plus Link TL. Output and build quality are what I've come to expect from this end of the market and the auto function is surprisingly useful. However, the need for a dedicated charging cable can be awkward, especially if you've run out of juice and need to refuel at the office or a friend's house.


Useful second light if you have a compatible Giant helmet test report

Make and model: Giant Numen Plus Link TL

Size tested: 20 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?

Giant say "Featuring a super bright COB outputting 20 lumens, Link has four modes with a max run time of 5 hours. USB rechargeable using the magnetic charging pod. (Fits Giant Roost, Strive, Strive MIPS & Prompt and Liv Coveta, Lanza, Lanza MIPS, Unica & Luta helmets".

My feelings "Overall, a surprisingly capable light if you have a compatible Giant helmet. Magnetic coupling system for charging may not suit everyone either."

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

* Output: Super bright COB, 20 Lumen

* Modes: 4; High / mid / flash / patrol

* Power: USB rechargeable

* Run time: Up to 5 hrs

* Mount: Magnetic

* Feature: Auto on/off, responds to the condition

Rate the light for quality of construction:



Generally good but rubberised switch cover wasn't the perfect fit it should've been on our sample.

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



Stable and secure magnetic mounts ensure a clean aesthetic too.

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



No problems to date, in the everyday sense.

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



Middling charge times and run times, by no means poor but still disappointing compared with some other brands' budget models boasting similar outputs and price tags.

Rate the light for performance:



Output and presence are pretty good across the board.

Rate the light for durability:



Build quality on par with others at this end of the market and generally good but switch cover was a potential entry point for water ingress on our sample.

Rate the light for weight:



Rate the light for value:



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

Overall, the Giant numen plus link TL is a surprisingly potent secondary light that, due in part to its location is more attention-grabbing than the 20 lumens might suggest. The intelligent auto sensor system, though nothing new (Shimano dynamo switches had these back in 2000) but effective and avoids unnecessary battery consumption. Magnetic, model specific charger has charm but I missed the option of being able to plug it in via micro-usb chargers.

Tell us what you particularly liked about the light

Decent output, sensible settings and sensor system.

Tell us what you particularly disliked about the light

Integrated design is a double-edged sword.

Did you enjoy using the light? Yes

Would you consider buying the light? Possibly.

Would you recommend the light to a friend? If they had a compatible Giant helmet

Use this box to explain your score

Neat and capable light but brand specific integration limits the appeal, especially since many standard blinkies with rubberised straps can be successfully helmet mounted too.

Overall rating: 6/10

About the tester

Age: 43  Height: 1m 81cm  Weight: 70kg

I usually ride: Rough Stuff Tourer Based around 4130 Univega mtb Frameset  My best bike is: 1955 Holdsworth Road Path and several others including cross & traditional road

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Experienced

I regularly do the following types of riding: cyclo cross, commuting, touring, fixed/singlespeed, mtb,

If you're thinking of buying this product using a cashback deal why not use the Top Cashback page and get some top cashback while helping to support your favourite independent cycling website

Shaun Audane is a freelance writer/product tester with over twenty-eight years riding experience, the last twelve (120,000 miles) spent putting bikes and kit through their paces for a variety of publications. Previous generations of his family worked at manufacturing's sharp end, thus Shaun can weld, has a sound understanding of frame building practice and a preference for steel or titanium framesets.
Citing Richard Ballantine and an Au pair as his earliest cycling influences, he is presently writing a cycling book with particular focus upon women, families and disabled audiences (Having been a registered care manager and coached children at Herne Hill Velodrome in earlier careers)

Latest Comments