What Our Gearhead(R) Experts Are Saying:"This one fills a gap a lot of people don't realize they have. It's got enough structure from the spread collar and ribbed cuffs to look put together, but the mesh side panels and roomy jersey construction mean it breathes through a warm session without issue. I've been wearing it untucked over shorts for outdoor training and tucked in for casual days. The curved hem makes both work. It's a simple shirt that just keeps getting grabbed."Warm days and long sessions call for something that can keep up without trapping heat. The Nike Button-Up Long-Sleeve Top brings mesh side panels into a roomy jersey construction that circulates air where you need it most, so you can stay covered without feeling sealed in. The front button closure and spread collar give it enough polish to wear well beyond the gym. Ribbed cuffs add a clean finish at the wrist, and the curved hem sits right whether you tuck it or leave it out. It's a straightforward shirt built around a simple premise: move freely, stay cool, look like you meant to wear it.