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Verdict: 
Well made, bright and easy to use, but with limited sideways visibility and no sideways mounting option
Weight: 
39g

The rubbery Knog Blinder MOB V Four Eyes rear light is bright and easy to use, but the side visibility is questionable in a light designed for commuting.

  • Pros: Bright; long battery life; quick to charge; easy to use
  • Cons: No sideways-mounting option; limited side visibility

Simple, strong and well protected, there's plenty to recommend the latest Knog Blinder MOB. However, in a light recommended by its makers for commuting, the V Four Eyes suffers from a couple of shortcomings.

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It comes with four LEDs, at least two of which are on at any one time. They're set vertically into a red reflective surround, which should satisfy the most pernickety of 'where's yer reflectors?' know-alls behind you. A max brightness of 44 lumens seems plenty to me, even in bright daylight, and from behind you will be seen by anyone troubling themselves to look. However, the flat display is mounted in a black casing that offers pretty well zero illumination viewed from the sides. Knog describes the 35 degrees beam angle as 'focused' but traffic-sharing commuters may want more all-round visibility.

The lamp unit is well and truly secured into the silicone back which also forms the mounting system. Knog promises it's 100% waterproof and it's proven so throughout testing. It looks like a light designed and built for the long-haul.

It's a good sign when you don't mind having to swap a test light between various bikes, suggesting that the mounting system is a good one. With the simple addition of a plastic cam clip, Knog has made it easy to stretch the silicone band around the seatpost. Three bands are supplied, the largest suitable for aero posts and the smallest meant for skinny seatposts. This is helped by the grip mountings being flexible too. road.cc readers have complained that these bands don't last long, but Knog has a reputation for good customer serviced so maybe just ask for some more if you have issues.

It's a pity that there's no way of mounting the light sideways, which seems an obvious thing you'd to want to do with such a long (7.5cm) light. Once in place it takes up most of your seatpost, so bear this in mind if you tend to have a lot of attachments.

Like most modern lights, how to attach it to a pannier rack is a puzzle.

> Buyer's Guide: 16 of the best rear lights for cycling

Charging is quick – just over 4 hours from flat. The light plugs directly into a USB socket but the little red 'on-charge' light is difficult to see in bright light. On full-blast, I got 30 minutes more than Knog's '2.6 hours' minimum run-time. I never got to the end of the battery on eco-flash mode. You can also put the light into 'storage mode' if it's not being used for a while – see the Knog website for details.

The five settings provided (two steady, three flashing) are all a rider really needs, in my opinion (feel free to differ), and are easy to scroll through, even from the saddle. The positioning of the on-off button on the back of the unit seemed odd at first, but I soon realised it made it easy to locate and press with a thumb, with the stretch of the rubber band helping supply the pressure needed.

The exposed USB plug is moulded into the rubber mount and really worried me at first, since it seems to be in the worst possible place for trapping moisture and corrosive road salt. But Knog says it's 'designed to be exposed to the elements, is waterproof and will not be damaged by exposure' and it has proved reliable so far.

As for value, its build quality and usability go some way to justifying the price, but there are cheaper options. The Blackburn DayBlazer 65, for example, is £27.99 (and a fiver more than the Knog gets you 125 lumens). Moon's Nebula is the same price, but you can mount it horizontally.

Bonus points to Knog for cutting back on the amount of packaging. The cardboard carton is actually made from sugarcane and is compostable rather than recyclable, whereas the minimal plastic wrapper is PET and can be recycled. I'd like to see a company go the extra mile and do away with plastic packaging altogether.

Verdict

Well made, bright and easy to use, but with limited sideways visibility and no sideways mounting option

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road.cc test report

Make and model: Knog Blinder Mob V Four Eyes Rear Light

Size tested: 26 x 76 x 62mm

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?

Knog describes this as "ideal for daily commutes".

Side visibility is limited by the flat display, which may not appeal in traffic.

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

LIGHT OUTPUT : 44 lumens

DIMENSIONS : 26 x 76x 62mm

WEIGHT : 39g

BEAM ANGLE : 35°

LIGHT MODES : Steady high, steady low, strobe, fancy flash, eco flash. Run times 2.6 to 55 hours.

100% WATERPROOF : The Blinder MOB is IP67 Tested and 100% waterproof against all elements

BUTTON : Longer button push on (0.75sec) prevents accidental turn on. Short presses switch modes continuously.

INTEGRATED USB PLUG : No charging cable required, plugs directly into USB ports & is designed to be exposed to the elements.

LEDs : Surface Mount (SMT) LED designed to provide maximum brightness level for up to 90% of the battery burn time for each mode.

CHARGE TIME : 4 -5 hours (LED will turn green when fully charged)

BATTERY : USB Rechargeable Lithium Polymer

BIKE ATTACHMENT : Tool-less removable silicone straps for posts 22 - 35mm+ diameter. Fits aero posts.

ACCESSORIES INCLUDED : 3x interchangeable straps for posts 22-32mm+ and aero seatposts.

Rate the light for quality of construction:
 
9/10

Simple, rugged and securely sealed. I liked this.

Rate the light for design and ease of use. How simple was the light to use?
 
10/10

Very easy to fit, thanks to the supplied cam lever for stretching the rubber bands. The function button, fitted on the back at the top, is easy to reach and use from the saddle. The light has mode memory so it comes on in the last setting you used.

Rate the light for the design and usability of the clamping system/s
 
7/10

A bit of flexibility in the mounting arms helps make a secure fit on a range of seatpost sizes. The plastic cam is a simple but useful addition that makes it very easy to stretch the silicone bands to fit. It's a pity you can't turn it sideways to take up less space on the seatpost if needed.

Rate the light for waterproofing. How did it stand up to the elements?
 
8/10

Seems supremely resistant to water penetration. I thought the exposed USB plug was a risky strategy, especially as it's likely to be pressed against the seatpost where water and grit could get trapped and cause damage, but Knog insists the plug is designed to be exposed to the elements and it has been fine so far. At least it's easy to clean before you charge.

Rate the light for battery life. How long did it last? How long did it take to recharge?
 
10/10

I got a full half hour longer than the stated 2.6 hours on full power. The claim on eco mode is 55 hours and I never ran it down in that mode before I remembered to charge it again!

Rate the light for performance:
 
7/10

At night, the light is highly visible from behind without frying the eyeballs of anyone following. Two steady and three flashing modes is all I want.

The full-power flashing modes are ideal for day riding.

The limited side visibility may be an issue in traffic.

Rate the light for durability:
 
9/10

The silicone case is resistant to dropping; there are no obviously brittle parts. I'll back this to last a few seasons.

Rate the light for weight:
 
8/10

For the quality and size, it's hardly excessive.

Rate the light for value:
 
6/10

Cheaper than some, more than others. It ain't cheap, but I would say the quality and usability up the value.

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

Very nice light to live with. As a commuting light, it lacks side visibility.

Tell us what you particularly liked about the light

Easy fitting and use, economical on power, well made.

Tell us what you particularly disliked about the light

It's long and thin so fills your seatpost. A sideways mounting option would help here. The side visibility isn't great in traffic.

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

A lot cheaper than many (mostly brighter) options, but the Blackburn DayBlazer range looks to offer better value: the 65-lumen is £27.99, the 125-lumen £44.99.

It's the same price as Moon's Nebula, which you can mount horizontally. 

For better side visibility (and a few more £££) look at the Cateye Rapid X3.

Did you enjoy using the light? Yes

Would you consider buying the light? Yes

Would you recommend the light to a friend? Possibly

Use this box to explain your overall score

It's well made, easy to fit and use, and a good bright light, but side visibility is quite poor, which for a light recommended for commuting is a bit disappointing.

Overall rating: 7/10

About the tester

Age: 52  Height: 6'2  Weight: 73kg and holding steady

I usually ride: Cannondale CAAD10   My best bike is: Tomassini Prestige

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

I regularly do the following types of riding: touring, sportives, general fitness riding, mountain biking