Ubiquiti have changed the name of a few of the NanoBeam devices to PowerBeam the units are the some the only differance is the name and part number.

NBE-M5-300 - Changed to PBE-M5-300 now part of the PowerBeam Range

NBE-M5-400 - Changed to PBE-M5-400 now part of the PowerBeam Range

NBE-M5AC-500 - Changed to PBE-5AC-500 now part of the PowerBeam Range

The Ubiquiti NanoBeam M range has a compact, all-in-one design with uniform beam width, efficient footprint and a faster processor. The Ubiquiti NanoBeam M can be easily mounted in a variety of ways thanks to the innovative mechanical design.