Perfect for water quality testing needs, the Oakton Waterproof pHTestr 10 measures from 1.0 to 15.0 pH with a resolution and relative accuracy of 0.1 pH. This hand-held tester also incorporates a large-screen display, automatic temperature compensation, memory back-up and auto-off feature to protect battery life. The Oakton Waterproof pHTestr 10 comes with a plastic storage case, hanging lanyard, four 1.5-volt batteries and a one-year warranty (six-month on replaceable electrode). Unit is 6.5 inches in length with a 1.5-inch diameter. Available separately, 4.0, 7.0 and 10.0 calibration solutions are recommended for use with this tester.