Binding is the process of uniquely associating receiver to a transmitter/transmitter RF module . A transmitter internal or external RF module can be bound to multiple receivers (not to be used simultaneously).A receiver can only be bound to one RF module.Follow the steps to finish the binding procedure. Put the transmitter/transmitter RF module into binding mode Connect battery to the receiver while holding the F/S button (hold for more than 6 seconds) on the receiver to enter the binding mode (red and green constant on). Press "bind" on the transmitter, the RED LED flashing indicates binding successfully. Reboot the receiver and go back to normal Mode of transmitter RF. Green LED constant on indicates linking normally. Color: Blue material: PC+metal Model: R1 V2 Mini Dimension: 17.2 x 8.8 x 4.5mm (L x W x H) Number of Channels: 16Ch Operating Voltage Range: 3.5V-6V Operating Current: 60mA@5V Operating Range: Full range Distance: 2KM Compatibility: radios in D16 mode Package Contents: 1 x receiver (with antenna) 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.