Comfortable Base Layer: Our men's long underwear features dual-layer engineering with Merino Wool fabric that traps body heat between the layers to provide a chill-blocking natural barrier of warmth Efficient Design: Our men's thermal underwear features convenient gussets and a comfortable non-itch waistband with a functioning front fly that maintains coverage and allows for freedom of motion during various activities Regular Fit: Our men’s long underwear boasts a tagless design and flat seams for a smooth, ultra-comfortable fit; Front and back rise feature true sizing for accurate fit Cold Weather Apparel: Our men’s long johns allow for minimal layering in extreme cold conditions during low- to medium-exertion activities; Perfect for casual or active wear Multi-Purpose Coverage: These ColdPruf Long johns for men sit at the natural waistline with a front and back rise that provides an exceptionally comfortable fit and maintains coverage during a wide variety of activities Flat Seams, Tagless and Front and Back Rise for Comfort