A “bumper” is an early automatic movement. Unlike a modern automatic, where the rotor spins a full 360 degrees, the rotor of a bumper moves back and forth about 130 degrees, bumping off of a pair of springs on opposite sides.
The “bumper” describes an Omega’s early automatic movements.
Omega bumper movements:
Caliber 332, Caliber 333, Caliber 342, Caliber 344, Caliber 351, Caliber 354 and others.
