pH 4 Calibration Fluid Solution 3 x Sachets pH Meters

PINPOINT High-Precision pH Calibration Fluids
4.000 +/- 0.002

These come in plastic envelope packets and are extremely accurate and field portable. Each packet contains ample fluid for calibration (about 30 ml). There is a free sample of these included with each PINPOINT pH Monitor and PINPOINT pH Controller. All electronic pH instruments should be calibrated monthly.