There is a total of two antenna sockets on the EZR13 extender. All of them are waterproof N-female connectors.
When installing the antennas, put extender and antennas in a vertical or horizontal direction to avoid bending the pins in the antenna connector. Twist the N-male connector on antennas in the clockwise direction to install the antennas on the router. Make sure the connection is tight.
The two flat sides on the default Omni antennas have a higher performance. Please adjust the antenna array as the below image shows to receive a better signal and avoid the interferences between antennas.
You can upgrade the WiFi antennas to directional panel or yagi antennas and improve the WiFi coverage in a specific direction. Make sure these antennas having N-male connectors. You can use either MIMO antenna or single-polarized antenna on the extender.