For those hot days getting after it on the trail come summer time, we're always thankful for the wicking, breathable performance of Mountain Hardwear's Crater Lake Shirt. It's made from a silky smooth UB Solar Knit fabric, which not only wicks sweat and cools us as we go, but also offers robust sun-protection with a UPF 50 rating to help us handle those cloud-less days at elevation.