The Model 520 has been designed to convert the Model 521 from an isocratic pump to a gradient HPLC system. Full operation and gradient control programming is achieved through the keypad on the front panel of the Model 520. The Model 520 includes a high pressure integral static mixer, connecting tubing, and all the accessories necessary to quickly convert the Model 521 to gradient operation. UHPLC (Maximum pressure: 15,000 PSI) is available for Analytical flow. Also Titanium pump heads and Biocompatible PEEK pump heads are available for all flow ranges. Titanium pump heads and Biocompatible PEEK pump heads are not listed below, please contact us for ASI part numbers. Dual primary pump heads are also available, please contact us.