The kit includes one pair of transmitter and receiver modules. And the frequency is 315MHz. It is very popular for remote control systems, such as wireless doorbell, remote control rolling gates, smart car, smart home, etc.
About the transmitter module (square shape):
- Compatible with Arduino
- Arduino Library: VirtualWire
- Working voltage: 3-12VDC
- Working current: 3.5mA
- Working frequency: 315MHz
- Transfer rate: 4.8kbps (max)
- Transmission distance: When the spring antennas are soldered to transmitter and receiver module and the power supply is 5V, the open area transmission distance can be increased to 40 meters. The supply voltage is larger, the transmission distance farther.
- Antenna: You can use the wire whose length is 23cm or the spring antenna for 315MHz RF.

About receiver module (rectangle shape):
- Compatible with Arduino, suitable for 3.3V MCU
- Arduino Library: VirtualWire
- Operating voltage: 2.5 - 4.5VDC
- Working frequency: 315MHz
- Working Current: 0.28mA (low power consumption)
- Sensitivity: -105db
- Antenna: You can use the wire whose length is 23cm or the spring antenna for 315MHz RF.
- Great for DIY project.