Seals play multiple key roles in cranes and lifting equipment. They effectively prevent the leakage of hydraulic oil, lubricating oil and other liquids and gases by filling or isolating the gaps between coupling surfaces, avoiding waste of resources and environmental pollution, while ensuring operational safety. Cranes and lifting equipment are often in harsh environments such as dust and humidity. Seals can prevent dust, moisture and other pollutants from entering the hydraulic system, gearbox and bearings, reducing corrosion and wear of components.