The Sharp pH Waterproof Tester is a durable, easy-to-use portable tester with a large display. The accurate and reliable Sharp pH Waterproof Tester offers two-point manual calibration, ±0.1 pH accuracy, range 0.0 to 14.0 pH, and environment 0-50°c / 100% RH. The new extended battery technology provides 1500 hours of battery life with auto shut-off after eight minutes. This tester floats, is pressure tested to six feet. Includes three 1.5v batteries and carrying case. Replaceable double junction pH glass electrode available.