This is the handheld device that automatically measures your pool's water conditions within 15 seconds. It removes all the guesswork employed by systems that require you to compare a test result with a reference chart. Dipping one of the 25 included test strips into the water and placing it into the tester delivers a precise reading of the three most commonly tested pool water parameters: free chlorine, pH, and total alkalinity. The easy-to-read LCD provides a clear digital readout of results, indicating if each of the readings are high, low, or within recommended levels--it also stores up to nine previous test results. Requires two AA batteries (not included). 5 1/4" H x 3 1/4" W x 1 1/2" D(8 1/4 oz.)