This is a popular active insulation jacket using Octa®︎. It is brand new and unused. The following is a quote from the manufacturer's description: This jacket is designed for active use, featuring a windproof and stretchy outer fabric, and a lining made of lightweight, sweat-wicking, and quick-drying Octa® with antibacterial treatment. It has a soft texture and excellent breathability. When stationary, the dead air contained within the hollow sections and eight protrusions of the material maintains warmth. The side panels use stretch material to follow movement, supporting high performance during mountain activities. ■Weight: 320g ■Material Outer: 20D 2-way Stretch Ripstop Main body: (100% nylon) Switching (separate fabric): (86% nylon, 14% polyurethane) Lining: Octa® (100% polyester) ■Features Quick-drying, antibacterial, odor-resistant, lightweight, stretch, water-repellent