A cold-weather workhorse, the icebreaker 260 ZoneKnit combines merino and precision ventilation for high-intensity movement in winter conditions.

A New Zealand Merino Pioneer

Since 1995, icebreaker has been proving that natural fibers can outperform synthetics in demanding mountain environments. By partnering directly with merino producers, primarily in New Zealand, the company emphasizes traceable fibre sourcing and high animal-welfare standards. icebreaker built its reputation on plastic-free layering systems and continues to champion merino as a renewable alternative to petroleum-based fabrics, particularly as concerns grow around microplastic shedding from synthetic garments.

Body-Mapped Ventilation with ZoneKnit

The 260 ZoneKnit Long Sleeve Half Zip for women uses icebreaker’s body-mapping construction to balance warmth and airflow. Targeted eyelet mesh panels are integrated into high-heat zones to promote breathability during sustained efforts, while the main fabric remains a solid knit. A half-zip neckline allows for quick ventilation adjustments on climbs or during high-intensity efforts in variable weather.

Designed with movement in mind, the top features gusseted underarms, raglan sleeves to reduce friction under pack straps and flatlock seams to minimize chafing. Plus, icebreaker merino wool is naturally movement-friendly and never feels constricting. Thumb loops help keep sleeves in place while adding coverage at the wrists, and a slightly dipped hem provides additional protection at the lower back.

Why “260”?

The “260” in the name refers to the fabric weight—260 grams per square metre—placing this piece in the warmer (but not warmest) category of icebreaker base layers. Compared to lighter 150- or 200-weight merino, 260 offers greater insulation and is best suited to deep winter conditions, cold resort laps or high-alpine touring. The denser knit traps more warmth against the body while still allowing merino’s natural breathability to regulate temperature. The ultrafine fibres help manage moisture, resist odour over multiple wears (read: the ultimate trip layer) and retain insulating properties even when damp.