SpecificationItem Type: Hydrogen Test PenMaterial: ABSH2 Range: 0 to 2400ppb, 0 to 2.400ppmResolution: 2ppb, 0.002ppmAccuracy: 10ppb, 0.01ppmTemperature Range: 0.1 to 60.0, 32.0 to 140Resolution: 0.10.1Accuracy: 0.5Working Environment: 0 to 60 (32.0 to 140), RH 90%Waterproof: IP67Battery: 3 x 1.5V Button Battery (LR44) (Battery Not Included)Product Size: Approx. 183 x 37mm 7.2 x 1.5inDisplay: LCD Digital Display with BacklitTemperature: Automatic Temperature Compensation 0 to 60Data Retention: Value RetentionAutomatic Shutdown: 5 MinutesH2 Calibration Point: 224, an Error of 20ppb is NormalApplication: Suitable for Swimming Pool Experiments, Hydroponic Foods, Aquariums, Gardening, Laboratories, Water Purification Drinking Water, Pond, Etc.Weight: Approx. 139g 4.9ozPackage List1 x Hydrogen Test Pen (Battery Not Included)1 x User Manual