The present invention relates to the field of apparatuses and methods of producing optical effect layers (OEL) comprising magnetically oriented magnetic or magnetizable pigment particles. In particular, the present invention relates to apparatuses comprising a first block (A) comprising a holder (1a) having mounted thereto a stator comprising n magnet-wire coils (1b) disposed in n annular slots of a magnetic-field-guiding stator core (1c), and a second block (B) comprising a casing (4), a rotor protection plate (2), a rotor comprising m permanent magnet poles (3a) of alternating polarity arranged around a circle in or on one side of a rotor disc (3b), and a permanent magnet assembly (PMA) (5), wherein the holder (A) is configured to be removeably fixed to a base of a rotating magnetic orienting cylinder (RMC) or a flatbed (FB) magnetic orienting printing unit and the second block (B) is removeably fixed to the first block (A).