Koo Open Cube sunglasses review

A smaller lens cycling sunglasses option for those who favour function over form

Koo Open Cube sunglasses
(Image: © Aaron Borrill)

Cyclingnews Verdict

Lightweight sunglasses with smaller lens and unique arm swivel design


  • +


  • +

    Clear field of view

  • +

    Quality on par with rivals

  • +

    Superb fit and helmet compatibility

  • +

    Array of frame colour and lens options


  • -

    More expensive than established brands

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Koo might be a new entrant to the best cycling glasses category but, in a relatively short space of time, the brand has managed to work its way into the top rungs of WorldTour cycling. A subsidiary of Italian helmet maker, Kask, Koo supplies both the men's and women's Trek-Segafredo teams with sunglasses - namely the Koo Orion and, the Open Cubes you see here.

Design and aesthetics

In much the same way as Rudy Project, the Open Cubes follow the same Italian way of doing things by trading the contemporary goggle-like appearance of its peers for a more traditional lens arrangement. The entire Open Cube range adopts a subtle colour palette with 12 stylish pastel hues to choose from. 

The sunglasses pictured are finished in what Koo calls pinegreen/white, replete with a complementing Zeiss-made ultra-white lens. A clear replacement lens is also included in the package for low-light winter conditions.


The glasses come in two size types - standard and Asian, both of which can be further broken down into small or medium options. Our medium pair offers an impressive fit and wide range of eye coverage despite the somewhat smaller lens shape. The Open Cube's party trick, however, is the way in which the arms fold away. In this case, a special pivot joint allows the arms to rotate inwards rather than fold in the traditional manner. 

The only difficulty comes when attempting to swap out the lenses - this can be a tricky and time-consuming exercise as it requires a deliberate squeeze and pull (around the frame temple area) to release the lens.

Riding experience

When it comes to performance, Koo has dialled in a series of vents in the upper frame to mitigate problems such as misting up when things start to get hot - particularly on a long, steady climb. The 16 per cent VLT-rated lens is superb as far as clarity and field of vision go, and do a stellar job at dismissing glare not to mention still providing impressive tonal range even in low-light situations such as tree-lined avenues.

The arms feature a 'Micrometrical Arm Adjustment' mechanism giving the sunglasses a three-way positioning system to tailor the fit to suit myriad helmet styles - no interference here. There's also an adjustable nose piece (available in two sizes) to further bolster comfort.


Are the Koo Open Cube sunglasses a value purchase considering the glut of performances options currently available? I'm inclined to say yes. What I like about Koo is that the Italian company is not easily influenced by what its rivals are doing and it shows in the design. I can't say I'm a fan of this particular colourway but there are 11 other options should this not tickle your fancy.

At $250 / £199, they're not the cheapest option in the segment but the original design, superb lens coverage and quality, fit and style will undoubtedly appeal to many cyclists. 

Tech spec: Koo Open Cube sunglasses

  • RRP: £199 / $250 / £199
  • Lens type: Ultra White, clear 16% VLT Ultra White, clear 16% VLT
  • UV protection: Yes
  • Frame: Half frame
  • Weight: 33g (actual)
  • Colours: 12 
  • Pro team: Trek-Segafredo

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