It was a standard TNC type omni antenna, 12 or 15dbi if i remember correctly…

From the router to the antenna the maximum cable length should be no more than 5 meters but you should use the minimum required (half meters or 1 meter if possible).

But to be honest we are using Ubiquiti routers nowadays with built-in antennas as they are far better quality and easier to configure and the firmware is more stable.