TSI AeroTrak Handheld Particle Counters offer many features and flexibility for customers interested in versatile handheld particle contamination monitoring. They offer 3 and 6 channel models and are all ISO 21501-4 compliant. The AeroTrak series are calibrated with NIST traceable PSL spheres using TSI’s world-class Classifier and Condensation Particle Counters, the recognized standard for particle measurements.