Knog Blinder 4V Rear Bike Light – Blindingly Good

KONG Blinder 4V Rear Bike Light

When a motorist comments, positively, on the brightness of your light, you know it’s doing its job. The Knog Blinder 4V is a compact, intense rear light designed with the usual attention to detail we’ve come to expect from Knog, and does its best to get you noticed for all the right reasons.  Looking for something compact, light, bright and portable?  This light is going to check all your boxes.

When you take the Blinder 4V out of its packaging it looks and feels like a well thought-out, well-designed little unit. Built from polycarbonate and aluminium, the Blinder 4V feels solid.  A lot of small lights feel too light or “plasticy” and the tabs or clips are prone to breaking.  The Blinder has an integrated rubber strap and steel clip that looks like it’ll grab onto nearly anything. Knog says that it suits 22-32mm diameter tubing and I found that the rounder the tube, the better the fit. For undersized or oversized tubes, or odd-shaped tubing, it is more difficult to get a fit, though the rubber strap still allows for more flexibility that many generic lights.  Knog are doing their bit for the environmental as well using fully recyclable packaging and enviro-friendly printing inks.

KNOG blinder bright rear bicycle light

The Blinder 4V is, like many of Knog’s lights, a one-button affair; long-press on, short-press to cycle modes, long-press off again.  This button is at the back of the unit, towards the top and you have to stretch the strap a little to move the unit clear of the seat post to operate it. This means that turning it on or off, or changing the flashing sequence is a task best performed when you have stopped and not while riding.

We reviewed KNOG Blinder lights earlier this year which had the same USB charging function as the 4V. Once it’s off the bike, the USB plug flips out from behind the clip area.  Given the bulk of the light, it won’t fit all USB ports.  Low fixed ports could prove troublesome, as you have to turn the light upside down to insert it.  Using a short USB extender cable would solve any problems, but you may not always have one on hand.

There is an LED next to the switch to indicate charging, full, or low battery.  It is very small, so it’s probably worth checking every few trips to make sure it’s not in need of a charge.

KONG Blinder 4V USB Charging

The Blinder on the Road
For my first ride I mounted the blinder on a 27.2mm seat post and rode home at dusk.  It was obvious that this was a brighter, more visible rear light than my usual Superflash knock-off light. If you glance behind you can see the Blinder 4V lighting up your bike’s back wheel, parked cars and the road around you. This is a BRIGHT light.

My usual dusk/dark commute rear facing lighting consists of the Superflash knock-off light on the seat post, a single-LED blinky on the seat stay and a helmet-mounted LED blinky. When it’s very dark I run a 4-LED flashing light on my backpack, too.  I’ve had comments from other cycle commuters about the level of lighting being very effective.  Never have I felt under-lit.

On my first ride with the Blinder 4V I had a driver stop and say “Wow, that’s an effective light!” Knog note that the light has an inbuilt 15-degree mount angle which means that the light unit is angled to point directly behind rather than down towards the road (at the same angle as the seat tube).  In practice the angle of change is minimal, though it is a nice thought.  The light mounts such that it’s not pointing in driver’s eyes, however.  This is a light that could easily distract other road users if it was poorly mounted.

Knog Blinder Angled Rear Bike Light

The light has 5 modes: solid, fast flash, organic flash 1 (‘heartbeat’), organic flash 2 and eco-flash.  I used it on fast flash and organic flash 1. The run time on for the eco-flash mode is claimed to be 50 hours, which is plausible given that it only fires two LEDs at a time.

The rubber strap seems a little counter-intuitive to install at first, being a ‘hook through and fold back around’ arrangement, but it felt solid.  Even so, I can’t help but think there was a small risk of catching baggy shorts on the clip and becoming unbuckled, though this didn’t happen during the time I was testing.  Should it undo on the run, there’s no safety net.  Given the length of the strap, the seat post or seat tube are the only options for mounting this light.  A low mounted saddle bag or short rise post may mean that this light won’t find a suitable mounting location on your bike, so ensure you have space first.

Knog Blinder Light Obstructed by a Saddlebag

The Blinder 4V is small, light, and unobtrusive enough to be left in place all the time, though it also can be quickly removed, which is recommended if you leave your bike locked up in a public space. The waterproofing is rated at IP66 (dust sealed, strong jets of water with limited ingress), so it should stand up to being doused with water from your back wheel or a rain shower.

Consider buying the Blinder 4V if:

  • You want compact brightness
  • You want to swap lights between bikes often without removing mounts
  • You want a less generic, better looking light


The KNOG Blinder 4V retails for $49.95 RRP and is available from KNOG online as well as in the many bicycle shops that carry this brand.

KONG Blinder 4V Rear Bike Light Sequences

Product Details:

KNOG Blinder 4V Rear Light (RRP $ 49.95)

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About The Author

is a road rider, a social rider (is there such a genre as serious social?) and cycle commuter.

14 responses to “Knog Blinder 4V Rear Bike Light – Blindingly Good”

  1. trailgumby says:

    Hi James, excellent review.

    One issue that I think needs to be addressed with bicycle tail lights is making the unit weather proof. The prospect of having a tail light fail in bad weather in the dark on a poorly lit road is somewhat chilling.

    Is this unit weatherproof?



  2. James Hutchison says:


    I’ve no reason to think this light is any less weather-protected than other offerings. The rechargable nature means there is no removable covers or pieces, no gaskets, seals or grommets. This should, in fact, make it more reliable in this regard.

  3. Jeff says:

    James, I find many lights adequate at night, and the darker the better. I want a light that will drill holes through following cars in sunlight. Can we measure this lights daytime performance?Thanks,

  4. Crawf says:

    If it’s anything like a knog boomer, then you better cross your fingers and have a backup light!

  5. trailgumby says:

    Hi James, thanks for the quick response.

    The lack of removable covers definitely sounds more promising, but I guess what you’re telling me is that Knog isn’t saying specifically that the unit is weather proof. I think it’s pretty safe to say that means it isn’t.

    Unfortunately, being mounted on the seatpost puts most rear lights directly in line to be constantly sprayed with water off the rear tyre, and I’ve not had many lights survive long – I’m an all-weather commuter.

    If they can make front flasher lights waterproof to 50m I dont understand why it would be any less important to offer the same advantage in a rear light. Yet almost no-one does.

    Thanks anyway. 🙂


  6. Shane says:

    Quote from the features of the blinder on knog’s website, “100% Waterproof: The Blinder 4V is IP66 Tested and 100%waterproof against all elements”

    Thanks to the review I just purchased 2 of these and will be using them at night/day and in all weather conditions. I’ll also be testing it side by side to my moon shield rear USB light (on flasher, testing battery duration, product longevity and brightness).

  7. James Hutchison says:

    I will let you know. But if you consider the photos above are all taken in daylight (albeit not direct sunlight), you can see there is a marked brightness level from the LED’s.

    The reply from Shane says what I meant to add. I’ve no reason to suspect this is any more or less weatherproof than my Garmin 305 or the Knog front lights.

    I’d consider this almost a step above the Boomer in terms of quality, having used many of Knog’s products since their first Frog models.

  8. trailgumby says:

    Thanks James and Shane. That is good news.

    And … well done, Knog.

  9. Shane says:

    Received my new Knog Blinders and can confirm that the mounting system is limited. As mentioned in the review it is designed to mount to a seat post or tube (tolerance: standard size or slightly smaller or slightly larger OK). I could mount to my square BMC seat post but not my ‘tear drop’ Giant ISP. I tried all sorts of ways to get it mounted to my 2009 Giant TCR Advanced and failed..the strap hook is just not compatible.

    Positive news is the quality is really good and better than moon shield IMO. It is just as bright as the moon shield, although due to the design of the 4 LEDs I feel it is more visible/noticeable.

    Yet to test battery life, all weather conditions and longevity but will post an update a few months of use.

  10. I was at KNOG (interview coming soon) and asked specifically about the waterproofing, it is fishtank waterproof with the IP66 classification meaning that it will withstand a high-pressure hose.

    With the USB part at the rear of the light, I was assured that the design means that even this part will resist water entering the unit.

    On the mounting system, I am allowed to say that in future we may see more flexibility however for aero profile tubes, it still will remain difficult with the ‘latch’ system of the blinders.

  11. Shane says:

    Battery life not as good as the MoonShield and other people I cycle with report that the KNOG isn’t close to being as bright as my MoonShield when both are being used at the same time during night time use.

    Overall, considering the strap system, battery life and brightness, I’m a bit disappointed in the KNOG blinder and probably won’t bother buying from them again.

  12. James Hutchison says:

    I have found battery life acceptable from mine (in the realm of 8-10 hours operating at various modes). The MoonShield is listed as 60 Lumens, while the 4V is 44. Are we getting into the realm of “too bright” here?!

  13. […] but it’s still a lock. We’ve reviewed a few knog products here on BNA, such as the knog blinder rear light, and we’ve visited the knog HQ in Melbourne. Yes, they’re an innovative design company […]

  14. Steve says:

    My light has been functioning perfectly, and I’m very happy with it. However, the mounting strap is already showing signs of wear/tear. Does anyone know of a way of mounting the light to the back of the bike; so that it is easy to remove and recharge? Thanks