Pen Type Digital Pocket Portable pH Meter Mini Water Quality Tester Checker 100% brand new ,high quality ,very accurate and durable Pen Type Meter that can simultaneously measure & display pH Electrode can be used for long time from the last calibration and in particularly taxing conditions Great for home and laboratory pH testing - aquariums, swimming pools, beverage Batteries: 3 x 1.5V(AG-13 Button Battery)(not included)