Features: COMBO V2 is tool board running Klipper firmware. Base on STM32F072, it provides two communication modes: CANBUS and USB. The onboards USB have up to three USB interfaces, which can be used to connect to the scanning leveling sensors (Scanners Leveling Sensors,such as Cartographer )and camera. It can also be connection vertically with optional board for easy use. Supports auxiliary board connection For front cover quick install & remove Support Onboards USB2.0, 3xUSB2.0 interfaces (one of which is located on the auxiliary board) Onboards CAN/USB switches.Onboards RESETS and BOOT0 button for easy firmware updated. Specifications: Component:ABS Size:Approx.41.8x47.8mm/1.65x1.88inch Package Includes: 1 Set Auxiliary Board note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.