DMSS 2.4GHz 6ch Add Receiver "RG613BX-B"
Use with RG613BX (R6A)(1ch to 6ch) you will be able to use 12ch
Dimension : 14.5 x 20.5 x 41.5mm
Weight : 12g
Receiving System : 6 channel DMSS System with XBus(7ch to 12ch)
Operating Voltage : 4.5-8.5V
Antenna Diversity Model
Antenna : Coaxial potion/105mm : Antenna potion/25mm
No telemetry 
Easy BIND system
Hard case