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Blackburn Mars 4.0 rear light



Deserves consideration, especially as it can be had half price online at the moment

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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Blackburn's Mars 4.0 rear light is a clever little light that comes with 3 different mounting options.

We really liked it when we reviewed its previous incarnation 4 years ago; though it's changed a bit since then, it's only got better.

It still has the amber side leds, but the 5 red LEDs on the Mars 3.0 have been upgraded and turned into one superbright 1 Watt LED, creating even more rear illumination. Whereas the model we reviewed then needed a screwdriver to undo the 3 screws that held the batteries in, the 4.0 unclips with a coin to change the 2 AAA batteries.

Not that you'll have to do that often, at 50 hrs runtime on full and a whopping 150 hrs on flashing.

As always with Blackburn stuff, the rear light is really well made, and the casing has stood up to the usual abuse and the wet weather we've been having over the winter. As with all their lights, this one too is covered with a lifetime warranty.

Apart from the overall goodness of this light, I was particularly impressed that it comes with a dedicated rack mounting bracket; something I usually have to DIY with other lights. It also comes with a tool-less seat post mount, and the light case itself has a belt clip which is what you clip into the bracket(s).

At 76 grams, it's not going to affect performance too much, and it will definitely get you seen in all but the brightest sunny weather.


Deserves consideration, especially as it can be had half price online at the moment.

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 test report

Make and model: Blackburn Mars 4.0 rear light

Size tested: n/a

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

* Blackburn's most powerful rear flasher

* 1 Watt ultra-bright red LED

* 2 Amber side LEDs for side visibility

* 50hr steady, 150hr flashing runtimes

* No tool battery installation

* 2 AAA batteries included

* 3 mounting options included: belt clip, seatpost clamp and reflector/rear rack mount

Rate the product for quality of construction:

The quality you've come to expect from Blackburn.

Rate the product for performance:

It really is quite bright for such a small light. The amber side lights help a lot, too.

Rate the product for durability:

These lights have a reputation for lasting a long time.

Rate the product for weight, if applicable:

76 grams, including batteries and seatpost mount. That's not a lot.

Rate the product for comfort, if applicable:

Once the mounting is in place, it's a doddle to use.

Rate the product for value:

Even at RRP it's value for money, let alone at half price currently available from Ribble.

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

It worked really well.

Tell us what you particularly liked about the product

It comes with a rack mount.

Tell us what you particularly disliked about the product


Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Overall rating: 9/10

About the tester

Age: 32  Height: 1.78m  Weight: 76kg

I usually ride: All of them!  My best bike is: Cervelo Dual

I've been riding for: Over 20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, touring, club rides, fixed/singlespeed, Audax


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