4Pcs NRF24L01+ Wireless Module with Voltage Regulating Breakout Adapter

nRF24L01 is a single chip radio transceiver for the worldwide 2.4 - 2.5 GHz ISM band.
With the on-board 3.3V voltage regulator. The module can accept up to 12V. Compatible with Arduino, Raspberry Pi.
Applications: wireless peripherals, remote control systems such as RC vehicles and consumer remote electronics, wireless voice transmission such as VoIP, wireless sensor networks, wireless networks, home and commercial automation.
Standard pin layout allows for easy connection to other boards.
You can find several resources available online easily, such as tutorials, data sheets, and notes.