Futaba R2104GF 4-Channel S-FHSS Receiver 4PL

FEATURES:

For use with the 4-PL S-FHSS four channel surface radio
High-speed mode (S-FHSS), with an output of 6.8ms accepts digital
servos including the BLS series and most peripheral equipment such
brushless ESCs
Flexible coaxial antenna that's easy to position inside a model for
ideal reception

SPECS:

Power Requirement: 3.5V - 8.4V shared with servos
Voltage: 3.5V - 8.4V
Dimensions: 1.54 x 1.02 x 0.39" (39 x 26 x 10mm)
Weight: 0.28oz (8g)