When you're making an epic ascent or trek, you want a sleeping bag that will keep you comfortable when the temperatures really start to drop. We've taken our best-selling Trestles Elite Sleeping Bag series and made our most sustainable sleeping bags ever, without sacrificing up-mountain performance or durability. The Trestles Elite Eco 0 Sleeping Bag is an environmentally friendly update which features Marmot Upcycle PFC-free and recycled shell, lining, and fill. HL-ElixREco Micro synthetic insulation uses a unique blend of three fibers for maximum warmth, soft handfeel, and high loft. Wave construction on top and a blanket construction on the bottom provide optimal warmth and comfort. An anatomically 3D footbox and a fold-down secondary zipper offer ventilation and easy access for this mummy sleeping bag. We designed the Trestles Elite Series for treks where every ounce counts, so we kept the lightweight and easy compressibility of the original. EN rated as comfortable for women to the comfort level of approximately 15.6 deg F and to a lower limit for men of approximately 2.3 deg F.