A WiFi extender, also known as a WiFi repeater or booster, is a device that amplifies the signal of an existing WiFi network to increase its coverage range. The extender receives the existing WiFi signal from the router and then rebroadcasts it to provide a stronger signal to areas where the original signal is weak or nonexistent. This is achieved by using two antennas, one to receive the existing signal and the other to transmit the amplified signal. A WiFi extender is typically placed halfway between the router and the area where the signal needs to be boosted. This helps to extend the range of the WiFi network, providing stronger and more reliable connections in areas that were previously out of range.