Includes a calibration solution! pH meter for ease of use. Pacer Measuring Device, Digipafer + 2 Calibration Liquid Set, Target Aquarium Features: A set of 2 popular pH meter and calibration liquid. This set allows you to measure your pH immediately. This pen-type pH meter allows you to easily measure your pH. Completely waterproof and replaceable electrode part. 2-point calibration for precision. The goal of ease of use and reasonable price. Set Contents: Pen type pH measuring instrument (electrode replacement type) x 1 pH 4.01 standard liquid (calibration liquid) 5.3 fl oz (150 ml) x 1 pH calibration fluid 7.0 5.3 fl oz (150 ml) x 1 specifications; Pen type pH measuring instrument (electrode replacement type); Measurement range: 0 - 14 pH accuracy: ± pH accuracy: 0.1 pH applicable temperature: 0 pH 50°C Battery: Button batteries LR44 x 4 [pH 4.01 standard liquid (calibration liquid) 5.3 fl oz (150 ml)] 4.01 ± 0.02 (25 °C)[pH calming solution] 7.00 ± 0.02 (25 °C)] pH meter: 6.70 x 37 x 37 x 37 x 37 x 37 x 37 x 37 x 37 inches (2 x 37 mm (2 mm) weight (approx) Meter: 2.8 oz (80 g). (Batteries included)