The Altitude Jersey combines modern ergonomic panels with Sombrio's Chill Mesh Lite technology. Carefully placed where you need it the most, Chill Mesh Lite allows your body to breathe better. Its xylitol treatment also has a cooling effect when it comes into contact with sweat. The perfect combination to keep you cool on the way up and on the way down. Plus, it has ¾ sleeves, which helps prevent scratches that can occur on extreme hikes.