This is a notice of intent to award a sole-source contract for annual service and preventive maintenance on a Rees Scientific Environmental Monitoring System. The work will be performed at the 374th Medical Group, Yokota Air Base in Japan. The anticipated period of performance is for one base year and four option years, from 1 May 2026 to 30 April 2031. The justification for a sole-source award is that the equipment and software are proprietary, making Rees Scientific Corporation the only available source. Interested parties may submit a capability statement to challenge this determination, but this is not a request for competitive proposals.