An intercomparison of eleven independently owned and operated axially scattering spectrometer probes (ASSP), active scattering aerosol spectrometer probes (ASASP), and classical scattering aerosol spectrometer probes (CSASP) aerosol-size spectrometers manufactured by Particle Measuring Systems, Inc. (PMS) was conducted to assess their measurement reproducibility and usefulness for describing the effects of marine aerosols on atmospheric transmission. Comparison of the dN/dr curves versus radius shows the consistency among probes. Extinction coefficients were calculated from measured particle-size distributions and compared with transmissometer, interferometer, visioceilometer, polar nephelometer, and horizon contrast photometric measurements to assess their usefulness in describing the effects of the aerosols on atmospheric transmission. A brief summary of the intercomparison data is presented. The results demonstrated that for properly operated, factory calibrated ASSPs and ASASP-CSASP combinations a) measured aerosol-size distributions were found to agree within an order of magnitude for visibilities encountered between 12 and 51 km, and b) extinction coefficients computed from the PMS measured aerosol-size distributions agreed within a factor of two to three with the other extinction measuring devices previously listed.