Filament Hooded Jacket S - Alloy/Jolt. Pack it for those days where you need just a touch of down insulation, or on those cold days on the chairlift when an extra layer might be crucial. Outdoor Research's new hooded version of the Filament has the same design as the popular hood-less version and a DWR-treated shell of ultralight 10D Pertex Quantum GL keeps moisture away from the premium 800-fill down inside.