The Particle Size Selector (PSS) allows you to control the lower detection limit of a TSI Condensation Particle Counter (CPC). The PSS is a separating device that selectively removes small particles from an aerosol by diffusion. Simply add or remove diffusion screens to change your CPC's lower cutoff point. It shifts toward larger sizes as more screens are added.

The PSS includes 11 screens and, therefore, can be configured for 11 cutoff points. An extra set of 12 screens may be ordered to expand the cutoff range further. Specific cut-off points vary based on the CPC's operating flow rate.