This is a governor, similar to what was once used on steam engines. It is meant to be attached to the drive train of a rotary device. As it spins, the arms are pulled upwards by centrifugal forces, causing the plunger in the center to move down. Normally this would be used to apply a brake to the device, slowing it down. Esentially, it's a primitive form of speed regulation.I built this without any application in mind, so it lacks attachment points and so on.Print one of each piece and assemble them with 40mm-long m4 bolts and nuts.