Mobility is the name of the game, and the Sierra Designs Women's Mobile Mummy SYN 1.5-Season Sleeping Bag provides plenty of it. The same Mobile Mummy now available with a synthetic fill. Poly Fiber offers great performance in warmer conditions. Moving when you do, it lets you easily sleep on your side, stomach, or back without feeling constrained. You can wear it like a garment to sit up and use your hands, or stow the foot box for a walk around camp.