This is a notice of intent to award a sole-source contract to Cytek Biosciences, Inc. for maintenance services on a specific Cytek flow cytometer (serial number Y1440). The requirement is for a firm fixed-price purchase order with a 12-month base period and four 12-month option periods. The work supports the Laboratory of Viral Diseases within the National Institutes of Health. This acquisition is set aside for small businesses under NAICS code 811210. The justification is that Cytek is the proprietary manufacturer and sole provider of maintenance for this equipment.