As opposed to the traditional “Uni-Syn” carb synchronizer or the arcane practice of sticking a tube in your ear and “listening to the whistle”, this is the best way to synchronize multiple carbs. A Uni-Syn acts as a second venturi in front of the carb, creating a vacuum which lifts a little plastic bead up a clear plastic tube, it offers a comparative reference only. A Synchrometer is an actual air flow gauge that gives a reading in kilograms per hour. They cause virtually no restriction and do not interfere with the operation of the carb. They are the only way to synchronize multiple Webers, since any airflow restriction will drastically change the Weber’s behavior. They are also immanently suitable for SUs as well. While a Uni-Syn requires you to rev the engine periodically to “clean out” between adjustments, this is not the case with a synchrometer, since it does not interfere with the operation of the carbs. Various fittings are available to adapt it to different carbs, such as Weber DGVs and small-throated SUs, or elbows to clear tight installations. (I'm looking at you, MG TF!)