X-431 SmartLink C HD (X-431 SmartLink C Heavy-Duty Diagnostic Module) is a Vehicle diagnostic interface mainly for commercial vehicles. With the cutting-edge dual processor, the X-431 SmartLink C HD is qualified for the majority of commercial vehicles maintenance requests. The SmartLink C HD will enable user with X-431 PRO3S+, X-431 V+ V4.0, etc. to work on both passenger and commercial cars.