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 will 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 , then find the ELRS option, enter and select BIND. After the frequency binding is successful, the LED light on the receiver will first turn off, then flash slowly and then stay on. Due to different batches, the appearance, color and printed words of the product , which will not affect the use. Type: 868MHz Material: PCB+metal colour: black Package Contents: 1 x Accessories 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.