This is an Arduino Can Bus shield. It is compatible with the Arduino standard interface and can be stacked on an Arduino UNO, Leonardo or MEGA board.
The shield integrates an MCP2515 CANBUS chip on the shield and has a CAN-BUS transceiver function. With an on-board DB9 and CAN-BUS connector you can choose a suitable port according to your host device.
There is also an integrated MicroSD socket for data storage - a perfect solution for data logging applications.
What is Canbus? Controller Area Network (CAN bus) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles, but is also used in many other contexts.