Designed for the pool professional. The tester's probe is dipped into a sample of pool water and the results are ready instantly. The Salt PockeTester measures the Sodium Chloride level in salt water pools with a range from 0 to 9,999 ppm. TDS is measured from 0 to 9,999 ppm and Temperature from 32.0° to 149°F. A memory feature saves up to 25 test results. The PockeTester is packages in a rugged carrying case with a special calibration standard.