Nice size and just right for R/C cars there are 3 sockets Ch1, Ch2 & B (battery) the B socket can be used for a transponder. Not a lot else to say. plug it in, bind it and it works!
Specification:
S-FHSS/FHSS (Auto Detection)
Dimension - 35x23x9mm
Weight - 6g
Rated Voltage - DC 4.8V ~ 7.4V
Operation Voltage - DC 4.0V ~ 8.4V