Particle Counter Standards are used specifically to calibrate laser particle counters and liquid particle counters that require a NIST traceable size standard with a very narrow peak standard deviation. Particle Counter Standards are highly uniform polystyrene microspheres calibrated within nanometers referenced to NIST SRMN size standards for size traceability. We use nanometer references below and 1 nm = 0.001 µm. We also provide silica particles from 40nm to 2000nm for the calibration of electron and atomic force microscopes. Particle Counter Standards are additionally used to produce PSL Wafer Standards used in the calibration of KLA and Hitachi wafer inspection systems. Particle Counter Standards are used to create aerosol size challenges to calibrate the size response of laser particle counters. Size calibration or surface scanning inspection systems, SSIS, is a requirement in the semiconductor industry. The 100 nm to 100 microns range of size standards can be used directly from the bottle without any dilutions at all. The particle size standards are diluted to the exact requirements for that size of particle and use in LPCs, laser particle counters. Minimal time is used to set your calibration tests. The spherical diameters are calibrated with traceability to NIST SRM size standards. The particle counter standards are packaged in Deionized water solutions of 15 milliliter (mL) bottles. The spheres have a density of 1.05 g/cm3 and an index of refraction of 1.59 @ 589 nm, measured at 25 degrees centigrade. Each bottle of particle counter standards contains a Certificate of Calibration and Traceability to NIST which includes a description of the calibration method and its uncertainty, and a table of chemical and physical properties. Polystyrene latex beads are lot-numbered for convenient technical service and support after the sale.