A wide range of hydraulic pumps are available, the two most common types which are applicable to the Jacks described in the former chapter are as follows: Hand-Operated Pumps for Hydraulic Return Jack. To be used as the hydraulic source for the hydraulic return jack of 720 kgf/cm2 series. Has a high and low automatic control-valve, the low pressure pump operates up to the loading of 30 kgf/cm2. This means larger output volume and higher speed without loss of capacity. As the safety-valve is recessed inside, operation is assured. Applicable to hydraulic spring return jacks.