Vent cool bump cap is the latest in head protection. Incorporating a light - Weigh ABS shell into baseball style cap, the outer cap is made using oversized mesh panel on the top of the cap, which allows for unbelievable airflow. - Vent cool bump cap is the latest in head protection. Incorporating a light - Weigh ABS shell into baseball style cap, the outer cap is made using oversized mesh panel on the top of the cap, which allows for unbelievable airflow.