Always the correct part
Sanwa RX-371W Waterproof 3-Channel 2.4GHz FHSS-2 Receiver. The RX-371W is a small, lightweight receiver that is compatible with all Sanwa 2.4GHz FHSS-2 frequency modulation surface transmitters. This receiver is waterproof and works equally well in cars, trucks and boats, and is a great option if you don't need more than three channels. The receiver has a nominal input voltage up to 7.4 volts, so you can power the receiver with a 2S LiPo battery and use high-voltage servos.
Nominal Input Voltage: 4.8v ~ 7.4v
Weight: 0.25oz (7.1gr)
Dimensions: 1.18x1.04x0.57" (30.0x26.5x14.5mm)
Frequency: 2.4GHz FHSS-2
Fail Safe Support: Yes (Throttle)