Adult Mummy Bag Reg 20 Degrees Ocean Blue. We’re constantly testing our products in the worst conditions all around the world to make our products perform even better. Explore how we test, and share your toughest moments of testing with us in the reviews below. The Adult Mummy Sleeping Bag has a lightweight durable 50D polyester taffeta shell, soft polyester pongee liner that’s warm to the touch, and is filled with a 4-hole hollow fiber polyester insulation to rate this bag’s comfort level at 20 degrees F.