No cover plate design, convenient for repairing and operation 2.Dual-cylinder lifting system, more stable and faster. 3.Cable-equalization system 4.Chain-driven system, faster lifting speed. 5.Single or double manual lock release system, safe and reliable. 6.Wear-resistant, heat-resistant and high strength macromolecular polyethylene slide blocks 7.Mold machining through the whole process so that the parts are universal and interchangeable 8.Automatic arm lock release 9.Automatic lifting height limitation. 10.Pass 120% capacity dynamic load test and 150% capacity static load test. 11.Italian oil seal to make sure no oil leakage 12.Optional manual pump on power unit in case of power off.