This is a 4CH RC Remote Control Circuit PCB Transmitter and Receiver Board. it has RC transmitter and receiver which has an Electronic frequency: 27MHz/40Mhz. The remote control distance of the RC transmitter and receiver, in the case of adequate electricity, without interference, the correct access to the antenna after about 10 m, above only for reference.   This module will only work with a good quality battery whose voltage should not go above 6v or below 3.7v. Don’t use this module with Lithium Polymer Batteries.