The Columbia Zero Rules Sleeveless Shirt keeps you cool and comfortable during dynamic aerobic activity in the heat. Soft, lightweight 100% polyester interlock fabric boasts comfort-stretch properties for enhanced freedom of movement. An antimicrobial treatment reduces odors to keep you fresher longer, while Omni-Shade UPF 30 sun protection helps shield your skin against harmful UV rays. Columbia's revolutionary Omni-Freeze ZERO technology reacts with your sweat to lower the temperature of the material. Omni-Wick advanced evaporation technology actively breathes and pulls sweat away from your body to keep you dry and cool. The classic V-neck design ensures a flattering, feminine fit. Modern Classic fit. Imported.