Knog Cobber Mid rear light review

Knog’s Cobber certainly looks different, but does its distinctive wraparound design deliver a visibility win?

Knog Cobber Mid rear light review
(Image: © Guy Kesteven)

BikePerfect Verdict

The excellent wraparound visibility and user-friendliness of Knog’s Cobber makes it one of our favourite rear lights if you can afford the premium price


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    Full power 330-degree visibility

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    Universal O-ring attachment

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    Built-in USB tab

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    Multiple presets, plus custom programming

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    Front and twin pack options

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    Fully waterproof

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    Proven reliability


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    Less power for the money than rivals

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It’s always good to get the chance to re-review a light that’s become a firm favorite in the years since we last threw our thoughts down about it, but we should probably explain why it’s one of our go-to pieces of safety equipment, and why we think it deserves a spot on our list of the best mountain bike lights.

Knog Cobber Mid rear light review

The Knog Cobber is a unique design with multiple mounting options for a variety of tube sizes (Image credit: Guy Kesteven)

Design and aesthetics

Knog has always done things differently since it launched its silicone-coated, built-in strap light and lock range years ago, so it’s no surprise to see the Cobber rear light looking so, well, different from the competition.

Apparently, 18 different factories said that the Cobber was too complex to build reliably, so to clear that concern up straight away, I’ve been running a Cobber Mid for two full years now. Despite having regularly dug it out from a fossilized state after off-road night raids or drowned it on relentlessly rainy road rides, it’s never flooded or faltered, and the waterproof design hasn’t even gotten misted inside. 

The only thing you’ll need to do is wipe and dry the built-in USB charging tab before plugging it in, but not having to remember a cable is user-friendly genius. While other brands have copied the idea, I’m pretty sure that Knog pioneered it, too, so props for that gift to the forgetful. While it’s only tiny, the single power and mode button is proud enough to be easy to access in winter gloves, while the press-and-hold ignition means you’re very unlikely to set it off accidentally in transit.

Knog Cobber Mid rear light review

With its wraparound design, it offers up to 330 degrees of visibility (Image credit: Guy Kesteven)


While we’re talking convenience, the curved back design obviously works superbly on tubes of roughly the same diameter — 20-35mm seat posts and handlebars — it still sits securely on square stays, kammtail seat posts, or awkward bar shapes, and it comes with an aero adaptor for bladed-style posts and tubes. Girth isn’t generally an issue either, as you get three different lengths of O-ring provided. This lets you pull and hook the light into place on any shape up to 200mm in diameter, and you can always loop a second O-ring on if you’re struggling. The only potential fitting issue is that thin or pointed seat post fins potentially need a shim or padding added, and two O-rings looping together. As well as keeping things very user friendly, the sliding mount over the built-in USB tongue design also keeps the Cobber impressively light for such a bright light.

How bright? With the Cobber Mid, you’re looking at a 170-lumen maximum output, but the fact it uses three LED strips side by side to create a constant curved wrap means that light is genuinely very visible through 330-degrees. A big difference to rear-focused lights where any leak of light to the side tends to be far less bright and noticeable in traffic. That’s one of the reasons I rarely go out on a group ride and someone doesn’t ask me where they can get one from. That’s before you talk them through the different brightness levels and eight different modes from three strobe and pulse settings.

If that’s not enough to play with, then you can download Knog’s Modemaker app to your PC, plug in your Cobber and create your own custom menu.

Knog Cobber Mid rear light review

170 lumens at maximum output offers excellent visibility at night (Image credit: Guy Kesteven)


The Knog Cobber Mid has been our go-to rear light option for years now and has never let us down, offering reliable performance and decent battery life. The 170-lumen max output and 62mm length of the Cobber isn’t quite what you want, there’s a 50-lumen, 33mm long Lil’ Cobber for $49.95, and a 270-lumen 93mm long Big Cobber for $89.95. Each has a brighter front equivalent, and the option to buy front and rear as a twin pack and save a bit of money (e.g. the Cobber Mid pair is $129.95).

Tech Specs: Knog Cobber Mid

  • Price: $69.95 / £62.99
  • Weight: 46g (with mount)
  • Max Lumen: 75 (steady)
  • Run time at full power: 2hrs 15mins (average of 3 runs max steady)
Guy Kesteven

Guy has been working on Bike Perfect since we launched in 2019. Hatched in Yorkshire he's been hardened by riding round it in all weathers since he was a kid. He spent a few years working in bike shops and warehouses before starting writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.

Current rides: Cervelo ZFS-5, Forbidden Druid V2, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg