The Arcteryx mens Atom Lt Jacket is a Coreloft insulated jacket with air permeable side panels for medium output activities. This layer functions as an outer layer or as a mid layer depending on the conditions. The fit is a trim hip length. The face fabric is a light soft fabric with good air permeability and a DWR finish to repel moisture. The insulation is Coreloft 60 providing warmth and comfort. The fleece stretch side panels are smooth faced and great for ventilation. There are zippered hand pockets and an internal zippered chest pocket and the hem is adjustable. The mid height insulated collar insures comfortable layering.