Arc'teryx Men's Gamma Lt Jacket 56% nylon, 34% polyester, 10% elastane GAMMA LT JACKET - The Gamma LT is the result of intelligent, purpose driven design and the Arcteryx commitment to craftsmanship. Made from lightweight, hardwearing Wee Burly softshell fabric, a DWR (durable water repellant) treated nylon/polyester double weave, the Gamma LT is strong, light and provides moderate warmth and weather protection. VERSATILE FABRIC - The fabric blends wind resistance with air permeable comfort, has elastane fibres for built-in two way stretch, and is exceptionally durable for its weight. Its wind and water resistance is complimented with a textured backing that adds thermal comfort and moisture transport during active use across a range of weather conditions and levels of activity. This versatile performance makes the Gamma LT an essential softshell for active alpine and backcountry endeavors. REFINEMENT AND INNOVATION - Refinement and smart innovation are Arcteryx design obsessions. To facilitate heat dump without inadvertent opening, the Gamma LT employs the ingenious No Slip Zip. The zippers unique construction involves a series of bumps on the top few teeth to prevent self-opening, but, as in many Arcteryx pieces, the zipper may be rapidly opened with a single hand for almost instantaneous heat dump. This seemingly little thing clearly shows the Arcteryx attention to detail. MOVEMENT AND FREEDOM - Alpine versatility requires exceptional freedom of movement, so Arcteryx leverages articulated patterning, underarm gussets and stretch materials to help the Gamma LT move with the body. JUST THE RIGHT FIT - The Arcteryx regular fit fits easily under a belay parka, allows room for midweight layers, yet is streamlined and athletic. The Gammas hip length hem and streamlined patterning allow it to lie comfortably under a harness or pack belt. Stretch gusset cuffs provide a secure fit, but push up easily for ventilation.