231 in³ (1 gallon) Reservoir Foot Treadle Operated, 4W/3P, 3,200 psi max. PowerX air over hydraulic pumps are designed to meet you high flow pump needs. Air Hydraulic Turbo speed operation offering high flow at high pressure 143 cu in flow at no load and 44 cu in flow at 3200 psi. Air pressure range 40-170 PSI with 1/4 18 NPTF inlet. Pressure relief valve for overload protection.