Features of the Mammut Men's Sertig LS T-Shirt Lightweight, comfortable, stretchable material Regulated moisture-wicking prevents rapid overcooling FreshTech antimicrobial treatment prevents unpleasant odors Flatlock seams for extra elasticity and to prevent abrasion Crew neck Lightweight with low packing volume Fabric Details 100% Polyester Insert material: 8% Spandex / 92% Polyester Weight: 152 g