According to the storage room classification
Hydraulic type - This type fills the upper part of the storage chamber with air, and the air and oil in the storage chamber mix to cause gasification. Gasification is generated during rapid or continuous operation and is also one of the causes of noise
Pneumatic type - This type fills the upper part of the storage room with gas (nitrogen), compensating for the shortcomings of the oil type, producing stable damping force and less noise.