The opaque construction and brushed back of the Vertexx fabric provide good heat retention, while its spandex content provides stretchability to ensure a comfortable fit.
The Brigade Balaclava is designed to fit under a helmet, and is made of moisture wicking Heatmaxx material.  It slips over the head and fits relatively loosely from the chin down to the neck.  The stretch seam around the face stays close to the skin though, which stops wind from flowing in.  The skin-facing side of the fabric is brushed for a soft, gentle feel, and also helps retain heat.