... to place MOQ:400PCS. 4 inch latest cooling fan(USB port fan)Power source plug: USBMaterial: MetalMeas(with box ... DC brushless motor, strong wind, super quiet. 2.5V USB(cable length:1.2m) power supply, metal shell, special ... cool and refreshing, comfortable. 11.USB plug and play,no external power needed,USB power adapter required for the 5V ... require MOQ400PCS). 4 inch latest cooling fan(USB port fan)