Neptune 560 Series Hydraulic Metering Pumps are engineered for higher capacities and available in either Simplex or Duplex. Neptune's Simplex design includes one micrometer dial and one liquid head. Neptune’s Duplex design are configured with two micrometer dials and two heads. Each pump comes with a variable Oil ByPass™ stroke adjustment feature which allows for better valve performance than variable linkage designs. The valve checks have extra time to seat even with heavy liquids since they are idle during the by-pass part of the suction / discharge strokes. Comes standard with 1/2HP-1ph-115VAC-60c-TEFC motor with other options available. Materials of construction options include: 316 Stainless Steel, Carpenter-20, PVC or PVDF Liquid Heads & PTFE Diaphragms. Capacities range from 40 gph (151.42 L/h) to 94 gph (355 L/h). Maximum Temperatures & Pressures: 316SS & C-20 - 200°F (93°C), 350 psi; PVC & PVDF- 125°F (52°C), 150 psi. Max Pressures apply on certain models.