This REED R3525-Kit pairs a compact, cable-electrode pH/mV meter with pH 4.01 and 7.00 buffer solutions for calibration right out of the box. It reads pH or mV alongside temperature at once, using automatic buffer recognition and 3-point calibration for reliable results. Ideal for water conditioning, aquariums, wastewater checks, and beverage production, it includes a protective holster, mounting suction cup, and 9V battery.