Sustainable design that doesn't sacrifice performance in cold weather around 30 deg F. The PFC-free, mummy-style Trestles Elite Eco 20 Long Sleeping Bag fill is made from 96% recycled material and has the lightweight, easy compressibility of the original. HL-ElixR Eco Micro synthetic insulation uses a unique blend of three fibers for maximum warmth, soft handfeel, and high loft. Wave and blanket construction plus a roomy footbox provide optimal warmth and comfort. A fold-down secondary zipper offers ventilation and easy access.