- You do not have any products in your shopping cart yet.
UYN Woman Biotrek Heavy Duty Socks - black/multicolor
(Product No.: UY-S100338-B857-35/36)
Maximum protection, maximum comfort, all in one sock. UYN BIOTREK HEAVY DUTY are the socks that combine high performance with a unique feeling of well-being thanks to the use of innovative biomaterials. The properties of fine merino wool are complemented by Kapok plant fiber, the lightest in nature, to ensure perfect thermoregulation even on the coldest days. The Natex fibre made from castor beans neutralizes odours and ensures dry feet on high-altitude hikes.
Find more products here
Find more products here
UYN Size Chart
Fit-und-Warm carries UYN for Casual, MTB, Road Cycling, Running, Trekking and Winter Sports for women, men and children. Relevant products include base layers, T-shirts, jackets and socks. UYN uses strongly product- and activity-specific apparel fits.
Unisex / Men's Socks
| EU | Foot length (cm) | US Men | UK |
|---|---|---|---|
| 35–38 | 23–24 | 4–5.5 | 3–5 |
| 39–41 | 24.5–25.5 | 6.5–8 | 6–7.5 |
| 42–44 | 26–27 | 8.5–10 | 8–9.5 |
| 45–47 | 27.5–28.5 | 11–12.5 | 10.5–12 |
Women's Socks – On Models Labelled Accordingly
| EU | Foot length (cm) | US Women | UK |
|---|---|---|---|
| 35–36 | 22.5–23 | 4.5–5.5 | 3–3.5 |
| 37–38 | 23.5–24 | 6–7 | 4.5–5.5 |
| 39–40 | 24.5–25 | 7.5–8 | 6–6.5 |
| 41–42 | 25.5–26 | 9–10 | 7.5–8 |
Apparel
| Area | Current official size selection |
|---|---|
| Men's technical apparel | XS to XXL; some products use combined sizes |
| Women's technical apparel | 2XS to XXL; some products use XS/S, S/M, M/L, L/XL |
| Fits | Aerodynamic / Slim / Regular / Comfort |
UYN provides the concrete size chart directly with each product. Because base layer, cycling, running, trekking and winter products use different constructions and fits, no third-party universal body chart is added.
Assortment check: Fit-und-Warm UYN brand page. Manufacturer sources: official UYN apparel categories/fit information and product-specific UYN sock size charts. Research checked on 20 August 2026.