Hanna dissolved oxygen meter model HI9143 

• Battery or VDC power When used for extended periods of time, there is no need to interrupt important tests, simply plug into a 12 VDC battery charger.
• Automatic Calibration Simply expose the probe to saturated air and press the CAL button. No need for messy solutions or tedious calibration processes.
• Extended Range The new and improved HI 9143 is supplied with an extended range of up to 300% and 45 mg/L of DO.
Cold, rain, snow, dust and humidity associated with use in the field can cause condensation which may damage a meter, rapidly deteriorating its performance and life. HI 9143 isdesigned for outdoor applications, especially waste water treatment and fish farming. Simple on-site calibration requires no chemical solutions. Just expose the probe to air and press the CAL button. In a few minutes the meter is calibrated and ready to use. Auto-calibration eliminates the need to use a screwdriver or other devices to adjust the reading. It provides readings of O2 (% or mg/l) and temperature and additionally supplies the user with compensation of salinity and altitude factors, plus compensation for temperature effect. HI 9143 is supplied complete with HI 76407/4 D.O. probe with 4 m (13') cable, 2 spare membranes, HI 7041S electrolyte solution, 4 × 1.5V AA batteries and instruction manual in a rugged carrying case.
Specifications:
Range: mg/l Oxygen 0.00 to 45.00 mg/L
% Saturation Oxygen 0.0 to 300.0%
Temperature 0.0 to 50.0 °C
Resolution: mg/l Oxygen 0.01 mg/L
% Saturation Oxygen 0.1%
Temperature 0.1°C
Accuracy: mg/l Oxygen ±1.5% Full Scale
% Saturation Oxygen ±1.5% Full Scale
Temperature ±0.5°C
Calibration: Automatic in saturated air
Temp. Compensation: Automatic from 32 to 122°F (0 to 50°C)
Auto Altitude Compensation: HI 9143 0 to 1900m (0 to 6230')
Resolution: HI 9143 100 meter
Auto Salinity Compensation: HI 9143 0 to 40 g/L (ppt)
Resolution: HI 9143 1 g/L (ppt)
Probe: HI 76407/4 Polarographic D.O. probe
Battery: 4 × 1.5 Volt AA / Power plug for 12VDC supply
Battery Life: approx. 200 hours of continuous use
Environment Temp.: 32 to 122°F (0 to 50°C)
Weight: 3.1 lb (1.4 Kg)
Dimensions: 7.7 × 3.1 × 2.4" (196 × 80 × 60mm)