There are currently five kinds of manometers--vacuum gauges--one can use to synchromize multiple carburetor throttles. The venerable bourdon tube (mechanical gauge) type, the mercury type, the water variety, various electronic types, and this kind, the steel ball type, one of the floating steel part category. See my article comparing many different kinds. Also take a look my article on synchronization.

Note: These tools are shown for informational and encouraging purposes. They are not for sale. Sorry. I can however advise you on sourcing.

Part 11