This Regulate Midlayer fleece by Helly Hansen is a versatile technical jacket that works as stand alone wind protector and as a heat regulating midlayer. Polartec 200g brushed fleece in main body with air pocket perforations Polyester shell outer fabric locks heat inside the air pockets H2Flow mechanical ventilation system for adjustable insulation level CIS Compatible Polartec insulation Polartec 200g brushed fleece in main body with air pocket perforations Polyester shell outer fabric locks heat inside the air pockets H2Flow mechanical ventilation system for adjustable insulation level CIS Compatible Polartec insulation Polartec 200g brushed fleece in main body with air pocket perforations Polyester shell outer fabric locks heat inside the air pockets H2Flow mechanical ventilation system for adjustable insulation level CIS Compatible Polartec insulation