This speaker Unit Driver is made of Neodymium magnet for good performance. Horn Driver Units are widely used in air defense alarms, car alarms, large highways, bridges, tunnels and other projects.Neodymium Driver Units are equipped with the industry standard 1-3/8"-male tread pattern. Shanghai Minsheng Electronic Co., Ltd. adheres to the business philosophy of "customer first, forge ahead" modern management methods are adopted to fully implement and implement the standards and methods of the international quality system. So that our factory has made great progress and better development. Ourfactory now has the ability to imitate according to the customer's samples and drawings. It can also be developed according to the internal structure of various police horns and driver heads and the performance required by customers.