Cole-Parmer Instrument Co., of Vernon Hills, Ill., offers Oakton Instruments’ new pH/DO 300 meters for the measurement of pH, dissolved oxygen and temperature. Switch from pH to dissolved oxygen with a push of a button. The pH/DO 300, which also floats, is waterproof and dustproof, making it suitable for applications that ruin ordinary meters. The meter includes a pH electrode and a DO probe with a 10-foot submersible cable—ideal for environmental, industrial, laboratory and water quality applications.