The National Institute of Standards and Technology (NIST) intends to negotiate a sole source procurement for Fluorescent Phosphate Optical Glass Units with Starna Cells, a specialized supplier located in Atascadero, California. This acquisition is essential for the NIST Biosystems and Biomaterials Division, as it aims to produce the NIST Standard Reference Material SRM 2943a, which is critical for fluorescence spectroscopy measurements. Starna Cells is uniquely qualified for this task, being the only U.S. small business capable of producing these specialized glass units, having over 40 years of experience in supplying similar materials. Interested parties may submit their capabilities for consideration by July 28, 2025, and should direct inquiries to Tish Walker at latish.walker@nist.gov.