The Transportation Security Administration (TSA) has issued a presolicitation for engineering modifications to commercially available stationary gantry/fixed source screening systems that screen checked bags for explosives in order to meet detection requirements to improve system throughput, reduce system and life cycle cost, and improve system reliability and availability, while maintaining security requirements. Multiple awards may be made. Sol. No. HSTS04-08-R-CT1125. Respond by June 16. Contact: Samantha Gray, contracting officer, 571-227-4174, [email protected].