The Clearwater series sleeping bags are made with MicroX+ insulation. MicroX+ Insulation consists of multiple denier staple-length fibers that have a siliconized finish for maximum insulation, loft, and compactness. It is an ultralightweight insulation that has a tremendous weight-to-warmth ratio. The Clearwater uses a 2-layer offset construction, sometimes called a "bag within a bag." The contoured hood and mummy shape helps seal up your warmth and keep you warmer. The Clearwater is a great backpacking sleeping bag to take along on yourhikes that won't take up all the space in your pack or weigh you down.