The Spresense extension board provides pin-compatibility with selected Arduino shields along with an SD card slot, a headphone jack and multiple microphone pins. * Audio input / output: 4-ch analog microphone input or 8-ch digital microphone input, headphone output * Digital input / output: 3.3V or 5V digital I/O * Analog input: 6-ch (5.0V range) * External memory interface: microSD card slot * Size: 68.6 mm x 53.3mm * Model name: CXD5602PWBEXT1 Any questions? Click here for SONY Spresense FAQs Github links: Spresense Arduino Library source git clone Spresense SDK source git clone --recursive