Refurbished Beckman Coulter Z1 Particle Counter (p/n 9914556). Overall Analysis Range: 1 µm to 120 µm diameter. The Beckman Coulter Z1 Dual Cell and Particle Counter unit was specifically designed for simple operations. It incorporates a unique, new oil displacement pump which delivers a high degree of accuracy and precision, and eliminates the need for mercury utilized in the traditional mercury manometers. Clear messages on the LCD display lead you through all set-up and analysis functions. Calibration requires only several keystrokes; optimum instrument settings are automatically computed and set. This model counts cells or particles in three regions, equal to or above the operator selected lower size, above the upper size setting and between the two sizes.