A helmet can comprise an upper-body comprising an upper outer shell, a first foam energy-absorbing material coupled the upper outer shell, and an upper vent opening formed through the upper-body. The helmet can comprise a lower-body nested within the upper-body, wherein the lower-body comprises a lower outer shell, a second foam energy-absorbing material coupled the outer shell, and a lower vent opening formed through the lower-body and overlapping with the upper vent opening. The helmet can comprise a vent closure system comprising a vent cover disposed between an inner surface of the upper-body and an outer surface of the lower-body, wherein the vent closure system is configured to adjustably block 0-100 percent of the overlap between the upper vent opening and the lower vent opening with the vent cover. An adjustable position of the vent cover can be determined by a position of a vent actuator tab.