The sleeping bag liner Sea To Summit Reactor Extreme w/ Drawcord with its mummy shape design and Thermolite® Pro fabric, incorporates innovative infrared technology and stretch material to provide extra warmth, versatility, and optimized insulation. The Sea To Summit Reactor Extreme w/ Drawcord also features a drawcord that ensures a perfect fit. This exclusive feature guarantees increased heat retention, ideal for cold conditions. Additionally, its durability is ensured by the use of 50% recycled Thermolite® EcoMade yarns and 50% Thermolite® Pro yarn.