ES900RX receiver frequency binding steps:1. Power on the ES900RX receiver, turn off the power immediately when the LED on the receiver goes out, and then repeat. After powering on the ES900RX for the third time, the LED light on the receiver start to flash twice, which means that the ES900RX receiver enters the binding mode. 2. Connect the ES900TX or ES915TX tuner module, select the CRSF protocol in the remote control module options, then find the ELRS option, enter and select BIND. After the frequency binding is successful, the LED light on the receiver first turn off, then flash slowly and then stay on. ES900RX receiver: Power input: 5V Working current: ~100Ma Working Agreement: CSRF Receiving frequency range: 868Mhz Size: 12mm X 12mm X 3mm Weight: 0.6 g (without antenna) Antenna terminal: IPEX1 Telemetry output power: Less than 17dBm ES900TX tuner module: Size: 55mm X 39mm X 11mm (only high frequency head module) Weight: 9.2 grams (tuner module only) Antenna terminal: SMA Input power: 5~13v, 5v~9v recommended Working frequency range:868Mhz Maximum output power: Less than 33dBm Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Colour:Gray Material:plastic Package Contents: 1 x Receiver Kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.