https://www.silabs.com/wireless/bluetooth/efr32bg1-series-1-modules/device.bgm121a256
BGM121A256 Smallest Bluetooth SiP Module - Silicon Labs - Silicon Labs
The BGM121A256 BLE module is the world's smallest Bluetooth SiP module that offers a complete, pre-certified plug-and-play BLE solution, accelerating design.
smallestbluetoothsipmodulesilicon