All synthetic insulations are not created equal which is why we choose Climashield XP to make our Yachiyo 30 a reliable go-to sleeping bag for almost any outing. Climashield balances warmth compressibility and long life. Intelligent design ensures function for everything you do—details like the Ergonomic Hood and Pillow Pocket improve warmth and convenience while keeping weight and size to a minimum. Feeling is believing though—slide into any women's Sierra Designs bag and you'll realize you're right at home.