The Lamina Z Spark Long Sleeping Bag from Mountain Hardwear features unique Lamina construction which maximizes the loft of your insulation, eliminates cold spots and thermally maps insulation to areas you need the most warmth. By strategically placing insulation, it is able to concentrate warmth where you need it most – around your core and feet. The comfort mummy fit of this 34°F/1°C rated bag offers room to move while remaining thermally efficient. It also features welded Lamina construction that maximizes loft and eliminates cold spots caused by traditional stitching. Soft polyester lining wicks away moisture and lightweight nylon shell repels water. Full-length zipper has double sliders for ventilation.