Product description

RadioMaster ER4 2.4GHz ELRS 4CH PWM Receiver

The RadioMaster ER4 is an ultra-lightweight 2.4GHz ExpressLRS (ELRS) PWM receiver designed for RC airplanes, small aircraft, boats, cars and other radio-controlled models. Weighing just 3 grams, it provides four direct PWM outputs in a compact package, making it suitable for lightweight builds where space and weight matter.

With automatic voltage telemetry, Wi-Fi firmware updates and WebUI configuration, the ER4 offers convenient setup and useful monitoring features for compatible ExpressLRS radio systems.

Key Features

• 2.4GHz ExpressLRS wireless protocol

• Four PWM output channels for direct servo connections

• Ultra-lightweight design weighing approximately 3g

• 15cm high-sensitivity antenna

• Automatic telemetry of receiver supply voltage or external battery voltage

• Wi-Fi firmware updates and WebUI configuration

• CRSF/SBUS serial output support

• Compatible with 2.4GHz ExpressLRS transmitters and modules

Technical Specifications

• Brand: RadioMaster

• Model: ER4

• Frequency: 2.4GHz

• Protocol: ExpressLRS (ELRS)

• Output: 4-channel PWM

• Serial output: CRSF/SBUS

• Operating voltage: DC 4.5–8.4V

• Telemetry power: 10mW, as listed in RadioMaster's product specifications

• External battery voltage detection: DC 4–35V

• Antenna: 15cm high-sensitivity antenna

• Dimensions: 30 × 15 × 5mm

• Weight: Approximately 3g

• Pre-installed firmware: ExpressLRS 3.3.0, according to the manufacturer's listing

Package Includes

• 1 × RadioMaster ER4 2.4GHz ELRS PWM receiver

• 2 × Heat-shrink tubes

• 1 × Type-A voltage telemetry wire

• 1 × User card

Compatibility note: Requires a compatible 2.4GHz ExpressLRS transmitter or external module. Check the transmitter's ELRS firmware and binding configuration before use.