This is a sole-source procurement for five commercial/off-the-shelf units of a flight-critical item, with award contingent on Government source approval. Only previously approved sources have been solicited because available technical data is inadequate for full and open competition. Non-approved sources must submit the source approval information required by the applicable NAVSUP WSS Source Approval Information Brochure with their proposal; offers missing required data will not be considered. The Government intends to negotiate with only one source under FAR 6.302-1, though responsible sources may identify their interest and capability or submit proposals or capability statements. If new-source approval cannot be completed in time or would preclude meeting Government requirements, award may proceed based on Fleet support needs.