The Mens Smartwool Microweight Crew is comfortable enough to wear alone or as a second layer. This Microweight Crew was designed with a crew neckline and the flatlock seam construction was implemented to reduce unwanted chafing. The Microweight Crew is made of 100% Smartwool jersey knit offering moisture control combined with a natural stretching fabric, making it soft and durable. The Mens Smartwool Microweight Crew should be a staple item in your closet that keeps you comfortable all year round.