It may not feel that chilly outside when you first hit the trail, but as soon as the clouds roll in and the wind picks up it gets pretty damn cold in a hurry. Be ready for changing conditions with the Arc teryx Men's Trino Jersey Jacket. WindStopper fabric on the chest and arms blocks out heat robbing wind, and it's also water resistant to keep you dry if you get caught in an unexpected drizzle or flurry. Stretch knit jersey on the back and underarms maintains breathability to allow heat and moisture to escape from the inside out, and it's stretchy for freedom of movement. An athletic cut keeps the fabric close to your skin for maximum warmth and moisture wicking, and a drawcord at the hem prevents chilly drafts. Multiple zippered pockets hold any small essentials you may need, such as keys or a phone, and reflective details improve visibility when you're running in low light.