Here's what other sites are saying:
The REI men's Venturi Quarter-Zip shirt delivers excellent performance on the trail. Even on the longest, most challenging days the Venturi ensures comfort to keep you going strong. Knit polyester/spandex blend provides 4-way stretch to enhance your comfort as you make your way down the trail. With a UPF 50+ rating, fabric provides excellent protection against harmful ultraviolet rays. Fabric wicks moisture, dries quickly and resists abrasion. Deep front zipper lets you adjust ventilation; collar is lined with soft, sweat-wicking polyester tricot. Shoulder seams are rolled forward to prevent chafing under backpack straps. Mesh panels are discreetly bonded to the fabric under the arms for venting. REI Venturi Quarter-Zip shirt has a classic fit.
- REI refers to the men's version