# What are the warmest winter base layers available? — Verified Specification Comparison

> All specification data verified from official manufacturer documentation.

What are the warmest winter base layers available?

## Products

### Meriwool Merino 250 Long Sleeves
```yaml
product: meriwool-merino-250-long-sleeves
brand: Meriwool
price_gbp: 48.06
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
weight: 312
material: 100% superfine 18.5-micron Merino wool
warmth_rating: 7.0
odor_resistance: Yes
```

- **Price:** £48.06 [^1]
- **Summary:** This midweight base layer uses 250g/m2 interlock-knit Merino wool for warmth, breathability, and temperature regulation. It is a slim-fitting option suited to winter layering, skiing, hiking, camping, and everyday cold-weather wear.
- **Ideal For:** It suits the search for the warmest winter base layers because its 250g/m2 midweight construction delivers a tested warmth rating of 7.0 while retaining Merino wool's natural odor resistance and insulating properties.

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## References & Sources
[^1]: Meriwool, accessed 2026-09-14. https://www.meriwoollayers.com/products/mens-merino-250-base-layer-long-sleeve