Product details:

The Marmot Ellie Short Sleeve features highly breathable, quick-drying/moisture-wicking AirExchange fabric with built-in UPF 30 sun protection that will keep you comfortable, while the open back yoke adds style and extra ventilation. Stretch construction makes it easier to move. The shirttail hem with side vents makes this a great layering piece over shorts, leggings, or jeans.