Apply for Farady transmissive and reflective optical Kerr effect. Can beproduced Zuo Cheng SB, SBV, WD, SG, shaped, and other means, the magnetic fielddirection can be Parallel to the ground can also be perpendicular to the ground,adjustable air-gap, single-yoke double yoke can light road directions optional.Farady effect of opening magnet pole axis of conical holes, cone angle usually14 °, very top of the first center hole to Φ2 ~ 3mm, can be more extreme headchange, can take care of Kerr effect experiment. It features easy to take up thesample, magnetic field gap can be adjusted for repeated measurements. User canthe required magnetic field space and the magnetic field of solenoid specialspecifications.