The simplex creates a 2:1 pressure ratio while the duplex creates a 3:1 pressure ratio. Wilden high pressure pumps do not require costly external boosters or amplifiers to achieve this pressure output. Our powerful solutions will create profitable results in your application. Designed Especially for applications involving High Discharge Pressure Ideally Suited for Filter Press Applications Sizes Available: 1”, 1 ½” and 2” Material of Construction: SS 316 (Stainless Steel), Aluminium, Ductile Iron, Polypropylene (PP).