The National Institute of Standards and Technology (NIST) is seeking sources to refurbish and upgrade aging hydrogen maser atomic clocks, which are critical for maintaining the official U.S. time standard, UTC(NIST). The requirement includes refurbishing three masers (e.g., inspecting bulbs, replacing ion pumps) and upgrading three masers to the MHM-2020 level (e.g., replacing control modules and wiring harnesses). No budget amount is specified in the description. The location for performance of services is not mentioned. This is a market research notice, not a solicitation, and NIST may pursue a sole-source award with Microchip Technology Inc. unless capable alternative sources express interest.