Mesh Bee is a 2.4GHz wireless transceiver mady by seeed studio. It uses JN516x wireless chip from NXP. It is open hardware, open source. The IDE and tools from NXP are also free.
At first, I bought two Mesh Bee modules. But the default firmware inside the modules are co-ordinator firmware. And I need to change one of them as end device. For that, I bought a UartSBee v5 and tested as shown in http://www.seeedstudio.com/wiki/Mesh_Bee.
To connect Co-ordinator to computer, I used UartSBee. For the end device, I used FTDI 3.3V cable with 3V3, TX1, RX1, GND connected via breadboard.
And I found that they worked correctly.