The MP pHTestr 30<191> is a New Generation pocket sized pH indicator of dissolved solids featuring:<195> Precision accuracy to ±0.2 pH<195> Simple push button calibration<195> Automatic shut-off<195> Easy-to-view LCD display<195> Error indicator<195> HOLD function.The pHTester 30 is easy-to-use, efficient, and fast. The housing is waterproof and dustproof, features a replaceable electrode and Automatic Temperature Compensation (ATC).