Radiomaster ER4 is a four channel PWM receiver for ELRS system on 2.4GHz. Thanks to PWM outputs, small size and low weight of 3g it is designed especially for smaller model aircraft or RC cars, where it retains the reliability, range and speed of the ELRS system. The receiver can be powered from 4.5-8.4V. It can be connected directly to a 2S Lipo battery. On the receiver EXT.V pad, which is used to measure the voltage of the drive battery in the range 4-35V. Like all ELRS receivers, the ER4 has telemetry.