Lightweight merino wool pieces can take you from the Mojave to Morocco, and are an optimal layering item when the weather is anything less than super hot. Duckworth’s Hummingbird Crew for women is extremely soft, with air-trapping ribbed fabric that allows you to maintain core comfort. The super-light wool keeps you warm when it gets wet and wicks moisture away from your skin, yet dries quickly, so is easy to wash in your hotel room sink while traveling. Layer it with other items to keep warm, or use it as a light shirt to keep cool and protected from the sun.