It is used for open and close the rolling door of supermarket door, storehouse, cinema, hotel, factory and so on. It can be operated by electricity and manual. Precise limit by the limiter controlled automatically. Operated by manual when out of power. Low noise, small shaking, low power exhaustion. Product Structure and Function Features 1. It can be driven by electricity to operate the functions of moving up and down, precise limit by the limiter controlled automatically. 2. Operated by manual when power off. 3 The motor is with overheat protect equipment. If the temperature up to 110, the power supply will be cut off automatically to protect the motor. Till the temperature down to 70, it can be used again. 4. Low noise, small shaking.