The STMicroelectronics X-NUCLEO-S2868A2 expansion board is based on the S2-LP ultra-low power RF transceiver and operates in the 868MHz ISM frequency band. The X-NUCLEO-S2868A2 interfaces with the STM32 Nucleo microcontroller via SPI connections and GPIO pins. You can change some of the GPIOs by mounting or removing the resistors. The expansion board is compatible with ST morpho and Arduino UNO R3 connectors.

S2-LP narrow band ultra-low power sub-1 GHz transceiver tuned for 860 - 940MHz frequency band
Programmable RF output power up to +16 dBm
Modulation schemes are 2-FSK, 2-GFSK, 4-FSK, 4-GFSK, OOK and ASK
Air data rate from 0.1 to 500 kbps
Ultra-low power consumption from 7 mA RX and 10 mA TX at +10 dBm