When it's so hot or humid that the thought of putting on a shirt makes you cringe, pull on the ultralight and breathable Royal Robbins Men's Solid Jasper Shirt. Its eco-friendly organic cotton and recycled polyester construction features a textured surface that slightly puckers to stay off the skin, so no more sticky shirt. And its sporty, sophisticated style means you can take this comfort on the town. Material: Organic cotton, polyester.