1.8000 series has aluminum die casting crust & aluminum crust total 2 kinds 2.Closing & latching speed can be adjusted Has the buffer function after door 65簅pened, and the function can be adjustable. 3.Has delay function 180-65癲oor closed, and the function can also be adjustable 4.Has an aluminum crust, door closer item 812-4 is advanced structure, stable performance.The speed valve locates over or below the door closer body to ensure it has a convenient & comfortable adjustment & operation circumstance. 5.Closing force can be adjusted for this 812-2 item. 6.Vertical, parallel or sliding rail installation style can be ed.