The DB2 is a expansion/daughter board that adds extra outputs and inputs to the NO2C v0.2.x, vCx and vDx. Two ignition outputs, several low current outputs and a sensor for constant barometric correction top the list.
The DB2 is currently sold in kit form, including the PCB and components. All components and connections for hooking the PCBs together are included. Engine wiring connectors are optional.
Additional information can be found on the Speeduino wiki here: https://speeduino.com/wiki/index.php/NO2C_for_Speeduino#DB2