"What Our Gearhead® Experts Are Saying:""I've been wearing the Black Diamond Lightwire Tech Short-Sleeve on everything from early morning gym sessions to afternoon trail runs and the underarm gussets are the detail I keep coming back to since I never feel restricted reaching for a hold or driving my arms on a climb. It breathes well enough that I forget I'm wearing a performance shirt, which is exactly what I want.""The Black Diamond Lightwire Tech Short-Sleeve T-Shirt is the kind of piece that earns a permanent spot in the rotation by refusing to be precious about where it gets worn. The polyester and elastane blend moves with the body and manages moisture well enough to stay comfortable through a hard gym session or a warm trail push without clinging or chafing. Underarm gussets open up full range of motion so nothing holds you back when the movement gets dynamic, whether that means pulling through a crux or just throwing a pack into the car. When the session runs long and daylight starts to slip, reflective logos keep you visible without interrupting the clean, simple aesthetic of the shirt. Regular fit and crew neck keep the silhouette versatile enough to wear well beyond the trailhead, making the Lightwire Tech a shirt that earns its keep across the full arc of an active day."