Lightweight Merino Wool Hat Solid: Lightweight Merino Wool Hat. Made of 100% natural Merino Wool, this is a light and versatile hat. Lightweight Merino wool hats are great as base protection layers for cold weather and are also fit for milder weather. Extremely soft feeling. Comfortable and natural fibers hat made of Merino wool. Ideal hat for use during low-medium intensity outdoor activities such as trekking, hiking and climbing. Design: Solid. One size.