Here's what other sites are saying:
NRS Men's Paddle Tops H2Core Silkweight Short-Sleeve Shirt - Men's Quarry S 1010803100. Short sleeves and relaxed fit keep you cool and comfortable. Provides advanced sun protection for SUP kayaking rafting and other active water sports. UPF 20 Relaxed fit for casual comfort and friction-free zones under the arms ensure comfortable paddling and rowing. Technical fabrics wick moisture away from the skin breathe freely and dry quickly for cool comfort on the water.