Features Convenient to Operate: Dissolved oxygen meter is equipped with 0% and 100% 2‑point automatic calibration buttons, convenient for calibration. Standard Temperature: Temperature compensation function automatically recognizes and converts corresponding value under the difference between actual solution temperature and the standard temperature. Detachable: The instrument can be divided into two parts, the sensor and the electronic unit, and the electrode can be removed and replaced. Professional Made: Sensor uses thin‑film dissolved oxygen electrodes, and the electronic unit is an integrated operational amplifier + microcomputer chip. Widely be Used: Mainly used in agriculture and aquaculture, water treatment, and also a good helper for household pet fish. Specification: Item Type: DO Meter Material: ABS Measuring Range: Dissolved Oxygen: 0-199.9%, 0-16.5mg/L Temperature: 0℃-50℃, 32℉-122℉ Resolution: Dissolved Oxygen: 0.1%, 0.01mg/L Temperature: 0.1℃, 32.18℉ Accuracy: Dissolved Oxygen: ±1.5%F.S (Full Scale) Temperature: ±1℃, ±33.8℉ Residual Current: The reading will not return to zero when ≤0.15mg/L Response Time: ≤15 Seconds Temperature Compensation: 0℃-50℃ Power Supply: 2 x 1.5V AAA Dry Battery (Battery Not Included) Working Temperature: 0℃-50℃, 32℉-122℉ How to Use: 1. Rinse the electrode with deionized water or rinse solution. Press On/Off to turn on the machine. Immerse the electrode in the zero-oxygen solution for at least 3 minutes and keep shaking gently until the displayed value is stable. 2. Press the on/off key until the second line of the "CAL" character is displayed, and gently shake the electrode. When the displayed value is stable, press the "%/L/mg" key, the display DO value is 0%, and the completion is zero. Calibration. 3. Clean the electrode, immerse the electrode in a saturated dissolved oxygen solution, and continue to gently shake the electrode until the displayed value is stable. 4. Gently shake and press the ON / OFF key until the second line of the display shows the "CAL" character, and then press the ℃/°F key, and the DO value of 100.0% will be displayed at this time, and the slope correction is completed. Package List: 1 x DO Meter 1 x Plastic Storage Box 3 x Sandpaper 1 x Electrode Protective Cover 1 x Manual Package List 1 x DO Meter 1 x Plastic Storage Box 3 x Sandpaper 1 x Electrode Protective Cover 1 x Manual