RX-471 2.4GHz-4ch FHSS4 107A41111A Include: Sanwa 4 channel 2.4GHz Receiver (1 pc) Specification: Nominal Input Voltage: 4.8-7.4V Weight: 0.23oz (6.6g) Dimensions: 1.18x0.91x0.55 in (30.0x23.3x14.0mm) Frequency: 2.4GHz FH3/FH4 Selectable Via Transmitter Fail-Safe Support: Yes (All Channels) Battery Voltage Fail-Safe Limit: 3.5-5.0V (FH3) / 3.5-7.4V (FH4)