Mini Siren MS - 190 is used on boat , police department, and vehicles as well . It can be used as a burglary system in automobile and building. It can also be used as indoor and outdoor . It's voltage is DC12v and 50 - 60 HZ . The ring gear and the casing are fixedly connected together, and the oil entering from the oil port pushes the rotor to revolve around a central point. This slow-rotating rotor drives the output through a splined shaft to become a cycloid hydraulic motor. After the advent of this cycloid motor, after decades of evolution, another concept of motor also began to form. This motor has rollers installed in the built-in ring gear. Motors with rollers provide high starting and running torque. The rollers reduce friction and thus improve efficiency. Even at very low speeds, the output shaft is Can produce stable output.