Under Armour HeatGear Sleeveless Vest (Black)

HeatGear Armour is UA's original performance baselayer, the one you put on first and take off last. So it's made extra-comfortable by wicking sweat and stretching so you can move no matter what. 

The super-light HeatGear fabric delivers superior coverage without weighing you down while the mesh underarm and back panels offer strategic ventilation. The ergonomic design of the vest keeps seams off high abrasion areas and increases durability. Also, the hybrid raglan sleeve construction presents you with an added range of motion and comfort.