Arc'teryx Sylan MEnhanced performance with zero distraction for fast running in technical mountain terrain. Matryx Micro upper weaves PU coated nylon yarns to deliver outstanding durability, fit, flex, and breathability for minimal weight Recycled polyester knit collar seals out debris and integrates with the tongue to create a secure, comfortable, sock like fit Tongue pocket secures the laces Extended U throat construction provides more flex, better breathability,