This is a non-competitive, sole-source solicitation for 20 units of a flight-critical part, where only government-approved sources have been solicited. The item requires Government source approval prior to award, and new sources must submit detailed technical data with their proposal to be considered. The time required for new source approval is typically too long to delay an award, so awards may proceed based on existing approved sources to meet urgent Fleet support needs. The performance location is not specified.