When the summer sun calls for coverage and the heat calls for maximum airflow, this short-sleeve shirt strikes the balance. Weighing just 189 grams in a size M, it packs back into its own pocket to toss in a bag for the trail or travel. With sleeves cut longer than a standard T-shirt, you get UPF50+ protection across your upper arms, shoulders and torso, while the flip-up collar gives your neck extra coverage.