Film synchronizer

Each gang consists of a group of large diameter sprockets on a common shaft.

A rotating knob on the front, which moves the threaded film through the gangs, operates the synchronizer's movement.

At the same time, there is a mechanical numerical counter which records the amount of film that has passed through the gangs.

The unit may have a counter that counts the number of frames, or the length of the footage.

The film editor may have a soundtrack on one gang, which can be read with an audio amplifier.