- Silja Half-Zip Base Layer Wool Top is a premium 100% Merino wool women’s baselayer top that gives you a feeling of warmth and Scandinavian tradition. It’s ooh-factor soft on the skin, breathable and naturally odor-resistant. Zip the high collar up into the chin guard if the wind threatens your snug. The subtle range of colors are all offset with a touch of Nordic-inspired class around the chest and upper arm.