The Nano-Air Light Vest is built from recycled ripstop polyester with a DWR finish made without intentionally added PFAS, so warmth doesn't rely on a chemical shortcut. FullRange insulation, also made from recycled polyester, delivers lightweight warmth that breathes instead of trapping heat as conditions shift. What Our Gearhead(R) Experts Are Saying:"I feel the ripstop dump heat the second I push the pace, then hold it again the moment I slow down to catch my breath. The insulation stretches with every reach on a scramble, so it never feels like it's fighting me."