The Women's ThermoBall Vest from The North Face is an ideal layer for high-energy. To keep your core warm, it's loaded with lightweight ThermoBall insulation that traps body heat in key areas. It’s just as compressible as down while being synthetic and insulates even when wet. It even stows in its own pocket when you don’t need it and a hem cinch cord helps lock in extra warmth, while secure pockets offer a place to stash small hiking essentials. With a sleeveless design, you benefit from core coverage and maximum arm mobility great when you are scrambling over rock ledges.