Proper synchronization of dual carburetor set-ups is essential for peak performance. Accurately dial in your carbs with one of these Carburetor Synchronizers. Our P/N: 5746 is the original, SU type, bubble gauge with pivoting gauge tube for down-draft or side-draft applications. The Pro-Synchronizer will not restrict airflow and feature an easy to read 1-30 kg/h numbered scale for precise synchronization. P/N: 43-5712 includes two boot adapters which allows for 1-tool usage on a wide spectrum of applications. P/N: 43-5718 includes one boot adapter.