The Power Grid™ fire resistant (FR) dual hazard 1/4 zip shirt provides maximum warmth to help you cope with the most extreme cold. 1/4 Zip Shirt is constructed with Power Grid™ 4-way stretch fabric that offers enhanced comfort and range of motion. The unique grid construction maximizes warmth, minimizes weight, and improves breathability. NEW for 2014: DragonWear decreased the fabric weight by over 20% while increasing the Arc Rating from HRC1 to HRC2. Plus, they improved the stretch to improve comfort and range of motion.