New for 2015! The Sierra Designs Women’s Backcountry Bed SYN 1.5 Season zipperless sleeping bag provides similar comfort to your bed at home. Synthetic insulation delivers reliable, cost-effective performance. Gender-specific construction on the Women’s Backcountry Bed SYN 1.5 Season bag offers a fit that is more proportional between the shoulder and hip girth for better thermal efficiency and includes a higher level of insulation to help offset a woman's natural tendency to sleep colder than a man. Now you can experience the same comfortable outdoor sleeping experience, with a synthetic fill.