The Air Force Life Cycle Management Center, KC-46 Contracting Division at Wright-Patterson Air Force Base, Ohio, is conducting market research to identify sources capable of upgrading APX-119 transponders and providing a rotational spare pool. The effort involves hardware/software upgrades for P/N 4079100 (dash numbers 0522 and 0531), with anticipated quantities of 190 retrofit units and 15 spare units, performed by an FAA Part 145 certified vendor while maintaining FAA STC compliance and using OEM service bulletin access. The selected contractor will receive units from the Government, ship the same number of upgraded units back without aircraft removal/reinstallation, and deliver units with at least a one-year warranty. Interested parties should submit a concise capabilities package of no more than five pages demonstrating ability to perform retrofits at up to 16 per week, relevant experience within the last 10 years, financial/capacity information, and business/socioeconomic details. This Sources Sought is for market research only, not a solicitation, and responses are voluntary with no reimbursement.