Norrøna Women's femund pureUll Zip Neck 26/27

PureUll is exactly what it sounds like — pure merino wool with no synthetic blend. Warmer than a blend for the same weight and better at handling odour, at the cost of abrasion resistance.

The choice between this and the equaliserUll blend comes down to how you'll use it. Pure wool for cold days and multi-day trips, where warmth and odour control matter most. Blend for daily hard use, where durability and drying speed matter more.

This is the one for genuinely cold mornings and for anyone who's decided synthetic base layers start smelling too fast. Wool handles multiple days of wear in a way nothing synthetic manages.

Wool also regulates in both directions, so it works on a twenty-degree tour and doesn't become unbearable when the sun comes out.

Zip neck for venting on the move. Fitted, as a base layer must be — it works through skin contact, and a loose base layer is just a thin shirt.