The only ones that truly cool are those with a cooling (Peltier element) plate. It's best to cool the carotid artery in the neck. The current consensus is that if the outside air is the same temperature as your body, a fan (electric fan) is just circulating the outside air (wind), and conversely, the heat generated by the motor makes it even hotter. Independent operation of just the cooling plate or just the fan is also possible. Built-in 6000mA battery Type-C charging Semiconductor Peltier element cooling Three-stage wind speed adjustment Negative ions Bladeless