Cast in comfort. This lightweight button-down is made of 100% recycled polyester yarns that provide UPF 50 rated sun protection and is distinguished by our clever PFG rod holder to help free up your hands. This fine-tuned design is made from Bluesign approved recycled polyester, it remains stain and water resistant, to keep you clean and comfortable all day. A Columbia short sleeve button-up that comes in many sizes and colors. Regular Fit. To ensure the size you choose is right, utilize our sizing chart and the following measurement instructions: For the sleeves, start at the center back of your neck and measure across the shoulder and down to the elbow. 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.