Boeri Siren Helmet - Women's The Boeri Siren Helmet provides an ultra-comfortable women's fit and keeps your head dry with seven passive chimney vents. A removable plug system lets you close off vents on really cold days and the fleece chin strap cover feels smooth against the face. Features: Seven passive chimney vents Removable plug system Fleece chin strap Soft ear pads and a removable liner Accepts RadioActive audio system