Oakton Traceable One-Shot™ conductivity and TDS standards include detailed KCl, NaCl, and 442 conversions, temperature corrections, and certified values referenced to 25C. Average accuracy at 25C is 0.25 microsiemens for 1, 5, 10 microsiemen (S) solutions, or 0.25% for all other solutions. The tested uncertainty is shown on the certificate, whichever is greater. Conductivity options range from 1 to 200,000 S/cm. Batch-tested solutions are lot certified; a few bottles from a single lot are analyzed