Specifications: BIND will flash for a few seconds, then the transmitter will beep indicating the process is complete. The LED on the receiver should now be solid indicating a successful bind has taken place. Remove the bind plug and store it in a convenient place. Note: 1. It's fit for DX3R DX2E DX4C DX5C spektrum transmitter except for DX4R. 2. Please check if your spektrum transmitter supports DSM2 protocol, If not, please do not buy, thanks for your understanding. 3.the receiver can not work with dx5 pro / dx4r transmitter well,please do not buy it Due to the hand measurement, there have size error about 1-5mm 4.Item color displayed in photos may be showing slightly different on your computer monitor Specification: 100% Brand new and high qulity Channels:3 Band:2.4GHz Modulation:Digital Spread Modulation 2 Dimensions (WxLxH):.85x1.30x.48(in) 21.6x33.1x12.35(mm) Weight:21oz (6g) Voltage Range:3.5V-9.6V Colour:gray Material:plastic Package Content 1x DSM2 Compatible 3CH Surface Receiver 1x Bind Plug