The Crowtail- Base Shield plugs into Arduino and is the foundation of the Crowtail system. ALL I/O ports of the Arduino are exposed and adapted into Crowtail connectors which include digital I/O,analog I/O,and specialized ports(I2C，UART) Shield Kit Arduin https://elecena.pl/product/6056933/crowtail-base-shield-for-arduino-2-0 2016-05-07 https://elecena.pl/product/6056933/crowtail-base-shield-for-arduino-2-0 2025-12-17