Buff Lightweight Merino Wool Hat - Gray, One Size. Merino wool makes this performance base-layer hat soft, comfortable, and naturally odor-resistant. Great for winter trail runs, springtime climbs, or autumn hikes. Features Lightweight wool fabric performs across a range of temperatures, dries quickly, and breathes to prevent overheating while on the move Wool is sourced from humanely raised, non-mulesed sheep Naturally odor resistant