The performance of conductivity probes are affected by use due to residue build up and aging.
M10031B is a lab grade 1413 µS/cm conductivity solution standard prepared against a NIST traceable potassium chloride solution that allows you to recalibrate your conductivity meter or tester. Check your meter or tester's manual to find the correct calibration standard for your meter.
Conductivity readings are effected by temperature. To help with this, a chart of the actual µS/cm value at various temperatures is printed on each sachet.
Milwaukee conductivity solutions are labeled with the lot number and expiration date and packaged in an air tight, tamper-proof sachet.