This is a market research notice from the U.S. Bureau of Reclamation seeking qualified sources for YSI EXO and YSI Pro-Digital water quality sondes, parts, accessories, and repair services. The equipment and services must be fully compatible with existing Government-owned YSI instrumentation, with no alternative brands considered. Repair and maintenance must be performed by Xylem Analytics or an authorized YSI repair provider. Performance of services is for the California-Great Basin Region. No budget amount is specified.