Atom Jacket Women's is an insulated jacket designed for trail activity, built as a breathable hybrid-insulated midlayer that provides reliable warmth for cold starts and changing conditions. Product Type: Women's insulated jacket. Material: Synthetic Fill. Lightweight Coreloft insulation is designed to resist packing out over time. Stretchy fleece side panels help manage heat and improve mobility. Layer under a hardshell to add warmth even in wet conditions. For trail layering, pair it with a women's shell jacket and a women's hiking pants . The Atom is the ultimate outdoor kit essential, delivering reliable, breathable warmth for chilly alpine starts and unexpected summit squalls. Built with lightweight Coreloft insulation that won't pack out (even after years of wear) and stretchy fleece side panels, it traps and dumps heat strategically. Slide it under a hardshell for a clutch layering system that'll keep you warm, even if it gets wet. What's been updated: Updated with recycled Coreloft™ insulation and DWR (Durable Water Repellent) free from intentionally added PFAS.