NRF24L01 + PA + LNA and external antenna Voltage: 3-3.6V (recommended 3.3V) V. Maximum output power: +20dBm. Power-down mode current: 4.2uA. Operating Range: 1Km Antenna Gain (peak): 2Dbi. 2MB rate (Open area): 520m. 1MB rate (Open area): 750m. 250Kb rate (Open area): 1100m. It uses 2.4GHz global open ISM band, with license free. SPI interface facilitates the communication with MCU I/O port.