Gregory Jade 28 Size:SM MD The removable battery pack can our 4D Brow Cooling The removable battery pack can be easily stowed in a pocket to preserve battery life with a cord long enough to reach those deep warm pockets for "polar mode The full length left side anti snag zipper and additional short right zipper let you control your comfort with precision and a cozy blanket like feel—while the ISO tested temperature rating means you can rest assured that your bag will hold up when temps hit freezing •Designed around the architectural principles of tension and compression seamlessly providing the padding and support needed to carry heavy loads