The A4VSO is a variable axial piston pump with an inclined disc for open hydrostatic circuits. It offers flow proportional to rotation and displacement, progressively adjustable. It is characterized by its excellent suction, nominal pressure of 350 bar, low noise, long durability, and support for radial and axial forces on the drive shaft. It stands out for its efficient power-to-weight ratio, modular system, short regulation times, through shaft for pump combination, position indicator, and mounting flexibility. It operates with HF fluids under reduced operating conditions.