Specification Item Type: Hydrogen Test Pen Material: ABS H2 Range: 0 to 2400ppb, 0 to 2.400ppm Resolution: 2ppb, 0.002ppm Accuracy: 10ppb, 0.01ppm Temperature Range: 0.1 to 60.0C, 32.0 to 140F Temperature Resolution: 0.1C/0.1F Temperature Accuracy: 0.5C Working Environment: 0 to 60C (32.0 to 140F), RH 90% max Waterproof Rating: IP67 Battery: 3 x 1.5V Button Cell (LR44), Battery Not Included Product Size: Approx. 183 x 37mm / 7.2 x 1.5in Display: LCD Digital Display with Backlight Temperature Compensation: Automatic from 0 to 60C Data Retention: Yes Auto Power Off: After 5 Minutes of Inactivity H2 Calibration Point: 224ppb, a deviation of 20ppb is within normal range Application: Suitable for use in swimming pools, hydroponics, aquariums, gardening, laboratories, drinking water purification, ponds, and other water testing applications Weight: Approx. 139g / 4.9oz Package List 1 x Hydrogen Test Pen (Batteries Not Included) 1 x User Manual