NIST’s Chemical Sciences Division is conducting market research to identify potential sources for a new Unipolar Diffusion Aerosol Charger (UDAC) to support aerosol metrology and chemical analysis. The charger must operate at volumetric flows of at least 1.5 L/min, place a unipolar positive charge on sub-micrometer aerosols, and enable calibration of condensation particle counters when used with an aerosol electrometer. Respondents are asked to provide company details, product specifications, pricing information, manufacturing location, and related services, but no proprietary information should be submitted. This is a sources sought notice for planning purposes only and does not obligate NIST to issue a solicitation or award a contract. Interested parties should respond as soon as possible, preferably before the notice’s closing date and time.