ExpressLRS Uses The Serial Protocol ( CRSF Protocol) To Communicate Between The Receiver And The Flight Board, So Make Your Flight Board Supports The Crsf Serial Protocol. The Nano Receiver Can Be Bound By Turning 3 Magnets, And The Nano Receiver Can Be Plugged And Unplugged 3 ; Make That The Led Flashes Quickly 2 , Indicating That The Receiver Processes The Binding Mode; That The Rf Tx Module Or Radio Transmitter Enters The Bound State And Emits A Bound Signal; If The Receiver Has A Stable Light, It Is Bound. Single-Sided Design Is More Convenient To Install The Circuit Adds Bpf+Fem Design, 100mw Backhaul + Higher Sensitivity 6 Stronger Anti-Interference Ability Faster Reception, Ipex1 Antenna Interface Frequency:2.4G Chip Type:Esp8285 MCU Rf Chip:SX1281 Minimum Refresh Rate:25HZ Maximum Refresh Rate:500HZ Input Voltage:3.6V-5.5V Antenna Interface:Ipex1 Colour:Black Material:ABS Size:Antenna Size:5.2x4cm,Chip Size:1.1x1.8x0.3cm Package Contents: 1 * Chip 1 * Receiver 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.