Baseball caps to be worn on a person's head are provided. According to one embodiment, a baseball cap includes a dome configured to be placed on the wearer's head, wherein the dome includes one or more panels and one or more cooling channels. The baseball cap also includes a hub positioned at a top of the dome. The hub comprises a central cavity and one or more conduits in gaseous communication with the one or more cooling channels of the dome. A coolant output port is provided in gaseous communication with the central cavity of the hub. The coolant output port is configured to supply a coolant gas to the one or more cooling channels of the dome via the central cavity of the hub.
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