The North Face Unisex Aleutian 0/-18 (Regular) Sleeping Bag Scallion Green/ Zinc Grey Left Hand This roomy, zero-degree, synthetic bag unzips flat for maximum comfort and four-season warmth. Sleep through the night while winter camping in a mummy bag that's insulated with reliable warmth of Heatseeker Eco and constructed with off-set quilting, a hood, and a draft collar to trap heat. The synthetic insulation achieves an efficient warmth-to-weight ratio and is highly compressible for easy packing. Trailhead Series Synthetic Mummy Bag