Standard features  capacity form 0.5t to 20t  gear assembly to be efficient for operation  drop forged hooks and hook holders to ensure superior quality and safety  asbestor-free brake discs  bearing mechanism to increase mechanical efficiency  g-80 load chain for sprocket made of alloy steel with precision machining has been got well heat-treatment  more thickness of sheet cover, gear cover and side plates for good quality  the static test is 4times of capacity, and running test is 1.5times of capacity one by one.