Assos Women's Ultraz Winter Long Sleeve Base Layer P1 The very warmest of the Assos base layer line, the Women’s Ultraz Winter Long Sleeve Base Layer P1 is for extreme cycling conditions, where temperatures plummet and keeping warm is vital. The heart of the base layer is a blend of merino wool and synthetic fibres. Together they provide a high degree of insulation against the cold, trapping warmth and preventing it from escaping while remaining quick to deal with sweat. The neck-warmer collar brings the cosiness high up on your neck for extra protection on particularly foul days. The high-stretch fit gives a comfortable layer that moves with you, while also improving moisture-wicking, rapidly moving sweat from your skin, critical for comfort when cycling in deep winter. The merino wool is naturally anti-microbial and is complemented with carbon fibre to boost freshness and anti-odour control. A seamless finish gives amazing comfort underneath any winter cycling jacket.