The North Face Men's ThermoBall Jacket is a lightweight synthetic insulation layer with seemingly endless applications. ThermoBall™ insulation features PrimaLoft® fibers that create rounded clusters that expand in a similar fashion to high-loft down. Synthetics still maintain thermal performance when exposed to moisture, so this jacket is a great option for wet-weather warmth needs. The low-bulk design is great for layering with other pieces, and you can also store it inside its own hand pocket when you don't need it.