The eSelect M series is a multifunction measuring instrument series with one (M1), two (M2), or three (M3) measurement parameters pH, Redox, free CHLORINE (residual), total CHLORINE, and conductivity. • pH and Rx can be selected on the same model • measurement of free or total chlorine: ion-selective membrane sensors, 0-2 Cl ppm; 0-20 Cl ppm; 0-20 Cl ppm (total); or open amperometric cell (Pt-Cu), 0-10 Cl ppm • Connection preparation for EtaCloud software; optional accessory: connectivity Kit.