Features 1、Dissolved oxygen meter is equipped with 0% and 100% 2‑point automatic calibration buttons, convenient for calibration. 2、Temperature compensation function automatically recognizes and converts corresponding value under the difference between actual solution temperature and the standard temperature. 3、The instrument can be divided into two parts, the sensor and the electronic unit, and the electrode can be removed and replaced. 4、Sensor uses thin‑film dissolved oxygen electrodes, and the electronic unit is an integrated operational amplifier + microcomputer chip. 5、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