M1100 CPD-HD™ High Dilution CPC is a condensation particle counting system with built-in high-dilution capabilities. A built-in two-stage, variable ratio diluter permits up to 15,000-to-1 in dilution for measuring particle concentration up to 1.5 x 108 particles/cc. The CPC-HD is ideally suited for measuring diesel exhaust particulates and highly concentrated aerosols from combustion or other sources.