Designed to trek incredibly lightly, this vented button-down is made of 100% recycled polyester—so it holds its own against snagged branches and brambles. Omni-Shade UPF 50 sun protection provide coverage when there isn''t a cloud in the sky. For non-stop comfort, Omni-Wick technology wicks perspiration and helps this shirt dry quickly, plus antimicrobial treatment keeps it fresh mile after mile. Features you''ll love include roll-up sleeves, dual chest pockets, and a classic shirttail hemline. Columbia offers this long sleeve shirt in multiple colors and sizes. Extended sizing available. Regular Fit. To ensure the size you choose is right, utilize our sizing chart and the following measurement instructions: To determine the neck size, measure at the base or thickest part of your neck. For the sleeves, start at the center back of your neck and measure across the shoulder and down to the sleeve. If you come up with a partial number, round up to the next even number. For the chest, measure at the fullest part of the chest, under the armpits, and over the shoulder blades, keeping the tape measure firm and level.