GoolRC Flysky FS-i6 AFHDS 2A 2.4GHz 6CH Radio System Transmitter for RC Helicopter Glider with FS-iA6 Receiver Mode 2 Reliable, interference free 2.4GHz AFHDS2A signal operation. Use only 4*AA batteries for transmitter. Digital receiver system. Quick and extremely stable in performance. Simple binding procedure.