[How to use it]The VCC voltage must match the working voltage of the module and remain in good performance filtering. Perfect kit: This kit contains 3 pairs of transmitter and receiver modules as as 3 pairs of antenna helical spiral spring remote control. And the frequency is 433 MHz. It is very for remote control such as roller gates with remote control, smart car, , etc. [Easy to use]Great influence on receiving the antenna module, preferably connected to the 1/4 wavelength of the antenna, typically 50 Ohm inductor. The length of the antenna is . 17 cm. Wireless transmitter modules: allow for your to communicate wirelessly with others for or high-frequency controlled devices that work at the same frequency (in this case 433 MHz). Warm tips: The antenna position also has the of the module, the installation, the antenna as directly as possible by the shielding, the high pressure and the interference source. The frequency used for receiving, decoding and oscillation resistance should match the transmitter. Colour: green Material: plastic + metal Package Contents: 3 x 433 MHz wireless transmitter module 3 x 433MHz wireless receiver module 6 x 433 MHz coil spring antenna Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.