OBD2 is basically just the second generation of the ODB world. It’s a more advanced technology and can provide better and more standardized vehicle protocols and system checks data. All OBD1 units required a corded connection, while newer OBD2 can be connected hands free via Bluetooth or Wi-Fi. ODB2 has become the standard tech at this point, so unless you are working on a vehicle that’s older than a 1995 model, that’s likely what you’re using.