Calibrate airborne optical particle counters (OPC) to comply with ISO 21501-4 regulations with the Thermo Scientific™ 4D Series Dry Microsphere Size Standards. Ideal for instrument manufacturers, as well as QA/QC managers in pharmaceutical, biotech and electronics manufacturing, these microsphere reference beads feature a calibration uncertainty—the range of values within which the actual mean diameter will lie—that is less than or equal to 2.5% of the mean diameter.

The diameter is traceable to the National Institute of Standards and Technology (NIST), and the product’s Certificate of Calibration and Traceability provides the documentation needed for QC/regulatory programs and audits.

• Mean size standard uncertainty of ≤2.5% enables calibration of air particle counters to ISO
• Superior uniformity provides exact calibration point when setting the calibration curve
• Diameter is traceable to NIST, a known government standard
• Certificate of Traceability provides objective evidence for QC compliance
• Available in 3μm, 5μm, 7μm and 10μm diameters
• Conveniently packaged in dropper-tipped bottles for direct dispensing into sampling chamber