Castelli NanoFlex 3G Armwarmers - AW19
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Castelli NanoFlex 3G Armwarmers - AW19Castelli NanoFlex 3G Armwarmers - AW19
Code: CS1952901
Castelli NanoFlex 3G Armwarmers - SS23

The Castelli Nano Flex 3G Arm Warmers are a stalwart of your winter cycling kit – rain repellent, windproof, warming and luxuriously comfortable, this latest evolution of the Nano Flex technology is Castelli’s best yet. The Nano Flex 3G fabric used across these arm warmers utilises a combination of newly updated durable water repellent (DWR) treatment and mechanical heat treatment to give previously unheard-of levels of rain protection. Light rain beads off the fabric, keeping you dry when those inevitable rainy spells descend. The flat-lock stitching and single-seam construction keep the profile of the warmers low and the stretch is optimised for maximal freedom of movement. A dual-sided silicone gripper at the upper end secures the warmers in place. The compact size of the warmers makes them easy to stuff into rear pockets when conditions lighten up. On the inside of the Nano Flex 3G fabric, a super soft finish and the optimal loft have been achieved through Castelli’s meticulous research and development. The fabric feels phenomenally comfortable against the skin and the loft traps just the right amount of air above the skin to keep your heat regulated over a wide range of autumn and winter conditions.


  • Newly updated Nano Flex 3G fabric for exceptional warmth, softness and protection from the rain
  • Minimal seam construction for aesthetic versatility and freedom of movement
  • Easily packable into a pocket
  • Highly breathable
  • Optimal temperature range is 8˚C – 20˚C

Sizing Information for Castelli Clothing:

Castelli Size Charts

HoneybadgerHad a “get down” recently (gotta love diesel on a corner) and trashed my old pair of NanoFlex. Had no hesitation in getting a new pair. Couple these with a Gabba top and you’re sorted for most UK conditions.
Mr RattnerLight spray simply beads. Relatively warm.
PeteClass product, as with everything Castelli you get what you pay for, can't recommend enough
Chris RowleyGreat for cooler days. Stay nanoflex coating keeps them clean from road spray
MarcoOrdered an L and it fits tight. For pure slim cyclists arms it's ok, however if you have a little more muscle structure I advise sizing up one. Quality is excellent
AndrewBeen searching for a dark blue arm warmer for years now I’m over the moon with my purchase top quality and stylish as always with Castelli at a bargain price from Merlin Cycles 😊
Edgar PetriccioneVery nice colour and material. Highly recommend.
Mr RossGreat! Super warm and aero, fuzzy comfortable and so far rain has beaded up off of them. Went for L arms and XL legs (6'2", 88kg)
Mr LicksComfortable and have a good fit.
MichaelGreat warmers. Good in the wet. The water will eventually get in but I'm still impressed.