Built-in Smart chip offers advanced functions and features to a stick style pH meter not found anywhere else The only stick style meter with: RENEW feature that tells you when it’s time to replace your pH electrode CAL feature that tells you when it’s time to recalibrate your meter Flat Surface pH electrode that is completely waterproof and rugged enough to withstand harsh environments Analog bargraph originates at neutral point (pH 7.00) to conveniently view trends in acidity or alkalinity ATC plus measures Temperature 1, 2 or 3 point calibration Extech Waterproof ExStik® pH Meter PH100$78.95 Need more information? Please feel free to contact us at 1-800-592-6940 - Ask for Extension 547 or Internet Sales.