Castelli Flanders 2 Warm Women’s Base Layer: Fleece Winter Layer (£70)
The Castelli Flanders 2 Warm is a women’s long-sleeve fleece base layer for cold-weather riding and running. We have not tested it ourselves. This page collects the listed fabric, weight and temperature range, and the Tredz price.
Available now: Castelli Flanders 2 Warm Womens Long Sleeve Base Layer — £70.00 at Tredz (RRP £90), correct at time of writing, 4 October 2026.
What the manufacturer and retailers list
- Fabric: retailers list Castelli’s SottoZero multi-denier fleece, 100% polyester, with underarm panels in 93% polyester and 7% elastane.
- Weight: listings quote 228 g.
- Temperature range: listings quote -2°C to 10°C.
- Fit: listed as regular, with a mid-height neck.
- Details: mesh inserts under the arms for ventilation and flat Merrow seams to reduce chafing.
Where it fits a triathlete’s winter
The points below are our reading of the listed specs, not test results.
- Cold bike rides and runs. The listed range of -2°C to 10°C covers most UK winter training mornings.
- Steady efforts rather than hard ones. A fleece layer suits steady rides and easy runs; a hard turbo session in a cold garage may feel too warm in it. We have not tested this.
- Women’s cut. This is the women’s version, so check Castelli’s men’s range if you want the unisex alternative.
- Price. Tredz shows it at £70 against an RRP of £90.
Where to buy
Tredz lists the Flanders 2 Warm at £70.00 at time of writing, and the link below goes to the same product page.
Related guides
See also our guide to the best cycling base layers, the best triathlon arm warmers and base layers and our review of the Castelli Core Seamless sleeveless base layer.
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