hi every one
we have 2 building with 3 kilometers distance, and there is a need to link these two building with WiFi, i want to know what product should i use to establish link in a distance less than 5 kilometer? i have been told to use MikroTik SXT Lite2 or Mikrotik SXT Lite5, which one should i use? another question, which band should i use 2.4Ghz or 5Ghz?
thx.

Use 5Ghz because is more reliable. SXT lite 5 will give you ~50mbps for 3km. Is better to use an kit with RB911G 5hnd and some dual pol antenna 19-23dbi (if you need more speed).