A WiFi repeater or extender is used to extend the coverage area of your WiFi network. It works by receiving your existing WiFi signal, amplifying it and then transmitting the boosted signal. With a WiFi repeater you can effectively double the coverage area of your WiFi network – reaching far corners, different floors, or even extend coverage to your yard. Just about any wifi repeater will work just fine. The Gazella team recommends TP-Link brand repeaters on the basis of performance and ease of use. You can purchase these on Amazon for approximately $20.