VW Bug, Super Beetle, Ghia And Bus Dual Carburetor Synchronizer Tools. Choose from the floating ball (SU) type sync tool or the what is commonly referred to as the snail type sync tool. The floating ball bubble gauge with pivoting tube is optimal for down-draft and side-draft carbs. The snail type pro-sync tool comes with 2 adapters for a wide range of carburetors, it also has an easy to read 1-30kg/h numbered scale. Perfect adjustment is imperative when trying to achieve max performance from a dual carb setup. Sold each.