Heavyweight Merino Wool Neckwarmer. The Buff Heavyweight Merino Buff is a comfortable and warm wool neck tube made of natural fibres. It's made from 100% Merino and is designed for protection in extremely cold conditions during low to medium intensity outdoor activities such as walking, mountaineering and climbing. Buff - Heavyweight Merino Buff - Fog Grey / Multi Stripe | Neck Gaiters | George Fisher UK