High reliability The rear of the plunger seal can be rinsed at any time; this feature ensures a longer seal life of the seal even when a high-concentration salt buffer solution is used as the mobile phase. The unique plunger holding mechanism also ensures a longer life seal, and high reliability. Exceptional ease of operation The flow rate or pressure is set via the numerical keys. The set flow rate, pressure, and the upper and lower pressure limits can be monitored at any time. Highly stable, fluctuation-free mobile phase delivery The compressibility of mobile phase is automatically controlled in the pump head according to the change in the back pressure by means of a high-resolution pressure sensor and a stepping motor. This feature minimizes the fluctuation of the mobile phase delivery. A variety of time programs The flow rate, mobile phase pressure, the ON/OFF of the solenoid valves, and the rinsing pump may be time-programmed through simple operation. This feature is quite convenient for column conditioning and automatic rinsing of the flow line.