This kit comes with one 315MHz transmitter and one 315MHz receiver.  They can easily fit into a breadboard and work well with microcontrollers to create a very simple wireless data link. Since these are only one transmitter and one receiver, they will only work communicating data one-way, you would need two pairs (of different frequencies) to act as a transmitter/receiver pair.

Note: These modules are indiscriminate and will receive a fair amount of noise.  Both the transmitter and receiver work at common frequencies and don't have IDs. Therefore, a method of filtering this noise and pairing transmitter and receiver will be necessary. The example code below shows such an example for basic operation. Please refer to the example code and links below for ways to accomplish a robust wireless data link.

Features:

• 315MHz
• 500ft range (given perfect conditions)
• 4800bps data rate
• 5V supply voltage

Documents:

• Arduino Library
• VirtualWire Instructions