For operation of rolling shutter of commercial and industrial Usage. Door weight 300kg ~ 1500kg. 1. Overworking for a short time. 2. Overheat protection. 3. Limit switch unit enables precise adjustment of door in up and down Positions. 4. Release chain in case of power failure. 5. Built-in control panel (KJ500C/KJ600C/JM500) 6. Control panel are available to infrared photocells, alarm lamp, and Remote control. 7. Safety device for preventing the vehicle or people from damage in Case of roller chain is break off.