If you haven't tried out a Buff on the trail yet, you're missing out. This thing is ridiculously useful and versatile. It's a neckband, balaclava, headband, and hat all in one ultralight piece of gear. If you pull it up over your nose and ears and add a hat you get awesome sun protection for everything above your shoulders. The fabric is lightweight and breathable so it doesn't trap heat, and is comfortable to wear for hours. It's also polygiene treated to inhibit microbial growth, so it doesn't get stinky when you're sweating (if you've used a sweaty balaclava before you know how crucial this feature is!). Plus they come in tons of fun colors and patterns. Pro-tip: dip it in a creek and wear it wrapped around your wrist to help keep you extra cool.