This is a sole source procurement for four TSI AeroTrak®+ Portable Airborne Particle Counters, including accessories and Installation Qualification/Operational Qualification services, from TSI Incorporated. The equipment is required for non-viable airborne particle monitoring to maintain regulatory compliance at the National Cancer Institute's Surgery Branch T30 Cell Production Facility. TSI is the only source capable of providing OEM-certified equipment and factory-authorized support; standardization avoids revalidation, retraining, and operational disruption. Although the government intends to award to TSI, interested parties may submit a capability statement demonstrating their ability to meet the requirement. The government will evaluate responses to determine whether a competitive procurement should be conducted.