The Wolf OBD2 Code Reader gives DIYers and hobby mechanics access to vehicle diagnostic information that would otherwise require a trip to a professional service technician. Modern vehicles rely on onboard computer control systems to manage performance, fuel efficiency, and emissions, and these systems self-test and store fault information that this reader retrieves directly from the vehicle.A backlit LCD screen keeps readings visible in different lighting conditions, and the unit powers directly through a detachable, heavy-duty OBD II cable rather than needing a separate battery. At 120 x 78 x 22mm and 250g, it's compact enough to keep in a car or toolbox for regular use during servicing and maintenance.