Under Armour The Original 9" Boxer Jock - Men's The Under Armour The Original Boxer Jock is made with a lightweight HeatGear® fabric that provides superior moisture transport to help keep you cool and dry. Articulated mesh crotch offers comfort, ventilation and support. Performance waistband, four-way stretch, working fly and anti-odor technology. 90% polyester/10% spandex. Imported.