Effetto Mariposa OctoPlus Helmet Liner

The Effetto Mariposa Octoplus Helmet Liner is a pack of foam padding, headlined by an eight-armed "octopus" of foam. It's designed to replace worn-out padding in any helmet thanks to its universal fit, but in reality it doesn't really suit modern helmets. There's a lot of wasted material in its packaging, too.

> Buy now: Effetto Mariposa Octoplus Helmet Liner Kit for £12 from Swinnerton Cycles

The Octoplus looks like the kind of retro product you might expect to find in the discounted bin in the corner of a local bike shop that's been around since the 90s. If you're struggling to picture what that might look like, take a look at Effetto Mariposa's video and you'll know the vibe I'm trying to capture.

As charming as this hark back to late 90s/early 00s "Made In Italy" cool is, the Octoplus Helmet Liner doesn't really work in the world of modern helmets.

2025 Effetto Mariposa OctoPlus Helmet Liner 4.jpeg (credit: road.cc)

Designed to replace worn-out padding in old helmets, the Octoplus is claimed to have a universal fit that "can be easily adapted to any road cycling or cross-country helmet, providing optimal comfort".

As you can see in the pics, the pads arrive as perforations in a big square pad of the same foam – sort of like a floppy Airfix kit. This leads to my first issue with it: the amount of waste. Once you remove all the individual elements, you have more foam left as waste than in the product itself. Not terribly eco-conscious packaging then...

2025 Effetto Mariposa OctoPlus Helmet Liner 3.jpeg (credit: road.cc)

Moving on, you're left with: a few Velcro tabs, four small foam circles, four larger circles, two rectangles, two longer rectangles, a chin strap, and the 'pièce de résistance' of the whole affair – the star-shaped "octopus" liner.

2025 Effetto Mariposa OctoPlus Helmet Liner 2.jpeg (credit: road.cc)

The chin strap has a piece of Velcro built in that enables it to wrap around a chin strap and stick to itself, while the other pieces of foam have a soft backing that attaches to the Velcro already inside your helmet.

I removed the (perfectly okay) padding from my Kask Protone and had a go at installing the Octoplus. The smaller elements worked quite well at replacing the smaller, regular shaped bits of foam. However, the star-shaped 'octopus' is just a bit too... unique... in terms of shape to work. It scrunched up inside the helmet and even with quite a lot of modification, I couldn't get it to offer as much coverage as the stock padding. The rectangular pieces around the brow of the helmet overlapped with the tips of the octopus, which affected the way the padding stuck to the helmet.

2025 Effetto Mariposa OctoPlus Helmet Liner 6.jpeg (credit: road.cc)

After quite a lot of fiddling, I still couldn't get the padding to really cover all the areas I wanted covered. The two prongs that came forwards towards the brow of the lid poked out the front-facing vent, while also creating adhesion issues with the element I'd installed across the brow. I'd trimmed and chopped a few bits off but I couldn't quite get it to work as I'm sure it's designed.

2025 Effetto Mariposa OctoPlus Helmet Liner 7.jpeg (credit: road.cc)

It's worth noting that in the video on Effetto Mariposa's website, the helmet used as an example is a pretty old school looking Bell or possibly Giro model, with much more 'traditional' sized and shaped vents. Modern helmets with aerodynamic cues – a broader variety in size of vents, and different vent placement to helmets of the early 2000s that all looked about the same – don't seem to quite line up with the shaping of this "universal fit" kit.

In use, the padding is quite comfortable, if a little bit thinner than the regular padding in my Kask. The padding itself seems good quality, and seems to 'self seal' after cutting, meaning no loose seams or threads that could accelerate wear. I did wash the padding to test its 'machine washable' credentials, and found it to lose a bit of its sponginess, and it's started to bobble slightly.

Value

The padding costs £12, which doesn't seem too expensive a way to breathe new life into an old helmet – although most manufacturers say you should be replacing your lid every three or four years anyway.

There are few alternatives out there from most main stream brands – beyond exact replacement padding for specific helmets – but the likes of Amazon do sell kits for around half the price or less that look to do much the same job, though I can't comment on their quality.

Or maybe you just need a new lid – check out our guide to the best cycling helmets.

Conclusion

Overall, though it's made of what seems to be high-quality foam, the Octoplus Helmet Liner kit is a bit old school. While the smaller elements could prove useful, the star-shaped 'octopus' didn't work well with my helmet – the claims of a "universal fit" don't line up with my experience, though it possibly works better with older style lids. On top of all that, the amount of material wasted is pretty unforgivable in my opinion.

> Buy now: Effetto Mariposa Octoplus Helmet Liner Kit for £12 from Swinnerton Cycles

Verdict

Some padding is better than none, but its 'universal fit' is a bit of a miss, and there's a lot of wasted material