Swiftwick Aspire Zero kari-traa Caffeine is proven to significantly

Caffeine is proven to significantly enhance high-intensity and endurance performance

and ready to tackle legendary trails

the computer-generated Clouds seamlessly collapse like dominos when your foot lands

rocks and obstacles

Let go – wherever you go

Swiftwick Aspire Zero kari-traa Caffeine is proven to significantlyOur most popular running sock and a great no show cycling sock. The ASPIRE is engineered with firm compression and a thin profile for a responsive feel. Firm compression supports every contour of the foot to reduce fatigue during endurance activities. Zero cuff height sits below the ankle with minimal extension above the shoe. Thin profile with light cushion Channeled upper improves breathability Lightweight Olefin fiber wicks moisture and dries