This carburetor synchronizer tool has been proven itself over and over, it is the most sought after tool for this job. The calibration feature allows user to calibrate the gauges before use, which is the primary reason many users choose this tool. This pressure gauge set can be used to test fuel pump pressure, emission control devices, leaking, stuck or burnt valves. It is an indispensable tool for motorcycle maintenance, getting the best performance out of your engine and reduce fuel consumption.