What's smaller than a Feather but larger than a Trinket? It's an Adafruit ItsyBitsy nRF52840 Express featuring the Nordic nRF52840 Bluetooth® LE processor! Teensy & powerful, with an fast nRF52840 Cortex M4 processor running at 64 MHz and 1 MB of FLASH - this microcontroller board is perfect when you want something very compact, with a heap-load of memory and Bluetooth® LE support This Itsy is your best option for tiny wireless connectivity - it can act as both a BLE central and peripheral, with support in both Arduino and CircuitPython