Specification Item Type: Hydrogen Test Pen Material: ABS H2 Range: 0 to 2400 ppb, 0 to 2.400 ppm Resolution: 2 ppb, 0.002 ppm Accuracy: ±10 ppb, ±0.01 ppm Temperature Range: 0.1 to 60.0 °C (32.0 to 140.0 °F) Temperature Resolution: 0.1 °C / 0.1 °F Temperature Accuracy: ±0.5 °C Working Environment: 0 to 60 °C (32.0 to 140.0 °F), RH ≤ 90% Waterproof Rating: IP67 Battery: 3 x 1.5V button cell batteries (LR44) (batteries not included) Product Size: Approx. 183 x 37 mm (7.2 x 1.5 in) Display: LCD digital display with backlight Temperature Compensation: Automatic, 0 to 60 °C Data Hold: Yes Auto Power Off: After 5 minutes Calibration Point: 224 ppb (typical calibration error up to ±20 ppb) Applications: Swimming pools, hydroponics, aquariums, gardening, laboratories, water purification systems, ponds, drinking water testing Weight: Approx. 139 g (4.9 oz) Package Includes: 1 x Hydrogen Test Pen (batteries not included) 1 x User Manual