Some aircraft provide a visual indicator of propeller synchronization in the cockpit.
Prop sychrophase acts much like a synchronizer to precisely match r.p.m., but the synchrophaser goes one step further.
A synchrophaser is also commonly referred to as prop sync, although that is not entirely correct nomenclature from a technical standpoint.
This gauge is also found installed with most propeller synchronizer and synchrophase systems.
Operation of propeller synchronization can occur with a primary/secondary approach or with a push/pull technique associated with Type II systems.
The net result is similar, but there is no primary or secondary, and no minute hunting typical of a Type I (primary/secondary) system.
With a Type II system RPM cannot be reduced below manual speed settings so prop sync does not need to be "Off" during takeoff and landing.