How to select hydraulic jack: 1. Thin hydraulic jacks are available in low space. 2. Select synchronous hydraulic jack when several jacks are used at the same time. 3. Self-locking hydraulic jack is selected for long time use. 4. Hollow hydraulic jack is available for tension and tension. 5. When the weight of 500t needs to be lifted, the uhp large-tonnage jack can be used. 6. Synchronous jacking system is optional for high progress synchronous jacking.