The ETA 2658 is a watch movement with a rotor placed out of center. It features an integrated winding gear, resulting in a remarkably slim design for its time. The movement has a detached manual wind function and employs a screw balance system, which was later replaced with a ring balance. Additionally, the split stem in Ocean Star models cannot be detached by pulling the crown but rather detaches when the movement is turned at the correct angle. As for its functions, the ETA 2658 movement is automatic and includes a sweep seconds hand.