Spresense is a compact development board based on Sony’s power-efficient multicore microcontroller CXD5602. It allows developers to create IoT applications in a very short time and is supported by the Arduino IDE as well as the more advanced NuttX based SDK. This extension board connects with the CXD5602PWBMAIN1 main board and provides Arduino Shield based connectors, SD card slot, 4 analog/8 digital microphone header and a headphone jack.