Men's Active Ultralite Short Sleeve

Fabric helps combine the moisture management, temperature regulation, and odor resistance of Merino with TENCEL™ Lyocell fiber to help keep you cool when your intensity amps up. ZQ-certified Merino wool (ZQ is the ethical sourcing standard that verifies animal welfare, environmental, and social practices across the wool supply chain) delivers the natural Merino performance — moisture management, odor resistance, temperature regulation. TENCEL™ Lyocell is a sustainably-sourced fiber made from wood pulp in a closed-loop manufacturing process that recycles water and solvents; it adds exceptional moisture-wicking, a cool-to-the-touch hand-feel, and a smooth drape that pure Merino jerseys can't match.

Super-light performance fabric — the lightest weight in the Smartwool tee lineup, engineered for high-output activity where a heavier tee would overheat and a pure synthetic would develop the clammy chill Merino avoids. The Merino-TENCEL blend dries faster than a pure Merino jersey and breathes better than a pure synthetic, so the tee handles the wide range of conditions a single workout or a full training day sees.

Our athletic fit is intended to be body-skimming to help keep the body moving freely — a slimmer cut than the Classic All-Season Crew's slim fit, designed to follow the body's contours through high-output movement without excess fabric billowing or catching in the wind. The athletic fit layers cleanly under a hydration vest or a pack without the bunching a looser fit would create, and wears cleanly on its own for the gym or the trailhead.

Offset shoulder and side seams designed to help increase comfort and minimize chafing — the shoulder seams are placed forward of the natural shoulder line so a pack's shoulder strap doesn't sit directly on the seam line; the side seams are placed to avoid the high-friction zones under the arm and at the chest. The result is a tee that doesn't develop hot spots under a pack strap, a hydration vest, or repeated arm movement during a high-output workout.

Reflective elements — placed where they catch headlights from multiple angles for early-morning runs, sunset trail sessions, and after-work training when the daylight fades. The reflective trim is integrated into the design without breaking the tee's clean silhouette.

Odor-resistant — the ZQ-certified Merino wool (53% of the fabric) naturally resists odor-causing bacteria, so the same tee covers multiple high-sweat workouts between washes. Multi-workout wear extends the fabric's lifespan (less washing = less fiber stress) and makes this a true workhorse training piece rather than a single-workout item.

Temperature-regulating — the Merino-TENCEL blend handles the temperature swings of a single workout (warm-up to peak intensity to cool-down) and the wider swings across a full training week. Merino manages the natural thermoregulation; TENCEL's moisture-wicking keeps the fabric cool to the touch during peak intensity. Together they deliver comfort across the full range of a high-output session without the chill-down a pure synthetic develops when sweat-soaked.

Built for the high-output uses where a Merino-TENCEL tee outperforms pure Merino and pure synthetic — pumping iron at the gym, hitting the trail for a hike, training runs, HIIT sessions, studio classes, indoor climbing sessions, and travel days. The athletic fit and the lightweight construction work across the gym-to-trail transition without the technical-performance look a base layer or a hiking-specific piece carries.

ZQ-Certified Merino + TENCEL™ Lyocell Blend; Athletic Body-Skimming Fit; Offset Shoulder & Side Seams; Reflective Visibility Elements