The 315MHz RF link kit is consisted of transmitter and receiver, popular used for remote control. We suggest you use the VirtualWire library for Arduino to use this kit. Please refer to the wiki for more details.
Specification
Frequency: 315Mhz
Modulation: ASK
Receiver Data Output: High - 1/2 Vcc, Low - 0.7v
Transmitter Input Voltage: 3-12V (high voltage = more transmitting power)