Perfect for conditions that ruin ordinary meters. The DO 300 meter is completely waterproof and dustproof with IP67 rating, and they float! No meter warm-up required, so you can take DO measurements right away. Independent 100% and zero adjustment calibrations and offset adjustment capabilities ensure high accuracy. These meters even display electrode diagnostics to help determine when probe needs replacing. The DO 300 meter features adjustable backlit display-ideal for dimly lit areas. Memory stores and recalls up to 50 readings plus temperature; real-time clock stamps stored data and calibration data with date and time. Key in salinity and pressure manually; meter automatically calculates offset values. Dual display shows mg/l (ppm) or % saturation plus temperature (°C/°F selectable). Automatic temperature compensation (ATC). Other features include Hold function, Auto-Off and Ready indicator. DO meter kit includes 500 mL electrolyte solution, five replacement membranes, membrane installation tool, rinse bottle and hard plastic carrying case. Dimensions: 7.5"L x 3.5"W x 1.75"H. Shipping weight: 1.4 lbs.