The Windridge is a versatile tee that is lightweight, breathable and well suited to anything from multiday treks to fast 5K's, days at the crag to sessions in the gym.
Marmot says:
Lightweight, breathable, and moisture wicking, the Men's Windridge Short-Sleeve Shirt was built for long days on the crag. As the hours are passing and the temps are rising, stay cool with side mesh panels that provide increased ventilation. Built-in UPF-50 sun protection shields your skin from dangerous rays. Forward-set shoulder seams ensure you stay comfortable whether you've got a harness or a backpack on, while flatlock seams reduce irritation and chafing. The drop-tail hem won't ride up and provides extra coverage as you scale the next pitch.
Marmot's Windridge SS Tee is great for warm conditions and intense activities. The lightweight fabric is breathable and has mesh panels for venting when things heat up. This tee is great in hotter conditions whether that's the weather or your activities as it dries quickly and provides protection from the sun at UPF 50. The synthetic fabric feels soft to touch and is comfortable enough for casual wear but works really well when you're going hard.
The seams are flatlocked for added comfort and reduced chaffing. They are also offset so they are good for wearing a pack and keep you comfortable with heavier loads. This tee has worked well on hot hiking trips in the mountains, trail running, rock climbing and pretty much every other activity I've worn it for.