XKG Foundation 150 Merino 1/4 Zip Review (2026)

Overview

The Foundation 150 is King's lightweight merino base layer: 17.5-micron, 150-weight fabric that's 90% merino wool and 10% nylon, with flatlock seams so it doesn't itch under other layers. Merino breathes when you're walking in and holds warmth once you sit, and it resists odor over several days in the field.

The quarter zip lets you dump heat on the hike in without pulling layers off. It has a 4.8-star average across 43 reviews on King's site.